Yes, someone has done this. My group last weekend in fact.
Three of us regulars all had one transport and so we decided to do it. Originally we were going to involve more people, but they all bailed so it came down to the three of us. I played the Imperials by myself and my worthy opponents split up the rebels.
For those who don't know the Rebels get three transports, all with free combat retrofits (+2 hull, +1 shield) and a free 10 point discount on upgrades. The Rebels then get 200 squad points for an escort. Imperials get a straight 250 points to crush this.
I really do think that the Imperials start coming into themselves once they get into Epic point scales. Fortunately I had thought I might have to run Imperials by myself and so I made a list that didn't have too many ships for me to run, but packed a lot of firepower to use against transports with no defense dice.
I would have run some form of miniswarm, I was seriously considering a bunch of black squads with ruthlessness because of how large transport bases are, but Imperial deployment prevents swarm play.
Imperial list:
Rexler Brath [Heavy Laser Cannon, Predator, Stealth Device] (50)
Patrol Leader [Darth Vader, Ysanne Isard] (47)
Captain Kagi [Advanced Sensors, Heavy Laser Cannon, Fleet Officer, Engine Upgrade] (44)
“Whisper” [Rebel Captive, Fire-Control System, Veteran Instincts, Advanced Cloaking Device] (42)
Soontir Fel [Royal Guard TIE, Push the Limit, Autothrusters, Targeting Computer] (34)
Mauler Mithel [Veteran Instincts] (18)
Black Squadron Pilot [Draw Their Fire] (15)
Rebel list:
We did this a week ago, so I might have forgotten a few things.
Deployment:



First you place the transports. Then the Imperial player places the four hyperspace tokens beyond range three of each other on his side. Then the Imperials place their ships within range one of each hyperspace marker divided evenly in numbers of ships. Then the Rebels place the rest of their ships within range 1-3 of their edge.
Then the fun part is the Imperials decide which hyperspace token the specific transports are gunning for. Victory for the Rebels is getting two transports to their tokens; the Imperials have to destroy two transports to win. I decided to cause a shuffle, but I didn't use the one that Rexlar and Kagi were on. I wanted them to have clear sights, and the shuttle was the only ship I was really worried about getting roadkilled.
I tried to make self-contained squads that would help each other. Rexlar with Kagi, the DTF Black squad with Doom Decimator, Soontir with Mauler, and Whisper by her lonesome (do note we used pre-FAQ phantom cloak).
The Rebels formed a gunline, with Etahn and two Bs against my Deci, Corran against Rexlar, and Tycho against Whisper.
First Turn:
Mostly just advancing. The exciting part was with the Decimator and Bs. They opened up against the Decimator and the Black Squad proved his loyalty by eating all of the Etahn crits, cause the Decimator to only lose its shields. Corran fired on Kagi, and Tycho tried to hurt Whisper but failed. Rebel captive was useless this game because Tycho was always the first ship to fire on Whisper. Who knew he was so heartless?

Second Turn:
Here is why my opponents' decision to rush at me with nothing in the back failed them. Whisper and Soontir blasted past the B-wings and opened up on the left transport. Fel also took his first damage from the slicer tools on the middle transport. Mauler had to barrel roll out of range 1 of a B. Amazingly the Decimator managed to get behind his opponents with a 3-bank. He opened up with the first Vader crit against the right transport. Corran ran into Kagi. He opened up both attacks on Rexlar, but didn't get through his stealth device (seriously, why don't more people take SD on Defenders?). Rexlar and Kagi did a number on the right transport with two focused HLCs. I forgot he had predator the entire game, good job me.

Third Turn:
This was the turn where my opponents use recover and took all those energy tokens shown above to get their shields back. Soontir was jammed and took another damage from slicer tools. Mauler maneuvered poorly and I got him runover by the left transport. I was rather disheartened.
Whisper did most of the damage back against the shields though on the left transport, and the Deci, Kagi, and Rexlar did a ton of damage and crits on the right transport. The recovery was the only thing keeping it in the game. Rexlar crits had caused it to be unable to turn or go fast forward or else it would take damage. Also my first command pod casualties crit was this turn. This causes two stress tokens to be placed on the rebel ships, one by the Rebel player and one by the Imperial. I choose to double-stress a k-turning B. Tycho is used as a stress dump. A heartless individual to be sure, so wantonly not caring about the state of his comrades.
The B-wings were off in la-la land this turn, trying to turn around and get at my ships which were now opening up full-boar on the transports. Corran k-turned, since he couldn't attack.
Fourth Turn:
Whisper was now behind the left transport, and continued to do four damage to it. Fel died like a ***** to jam/slicer tools. I should have looked at the transport upgrades better before designing my squad. I'm not sure why I brought a PtL interceptor to a transport party. I thought I'd use him to kill a large turret ship, but no such luck.
The Decimator pulled a fast one and moved over to attack the left transport. Down to two hull, most of which had been used on Vader crits on the transports.
Rexlar was going to k-turn, but Raymus Antilles was used to make it a red maneuver like lesser craft's k-turns. Antilles causes you to look at an opponents maneuver and make it red if it is white. I was still able to get him a focus from fleet officer. Combined with Kagi, I was able to blow up the right transport. First Transport down!

Then Kagi died to the concentrated fire of Corran, Etahn, and two Bs, all with Etahn crits.
The fun thing that happened this turn was my opponent accidentally put a red maneuver on his stressed B-wing (the one I had double stressed with pod casualties crit even), so I sent it ramming right at the transport. The only non-transport ship I was able to kill.

Fifth Turn:
At this point the middle transport is getting away. It's still at full health and at most two turns from getting out. The damaged transport meanwhile is down to five health. I have to kill it.
Tycho continues to fail to get his two damage through Whisper uncloaked. Whisper however flubs her roll and I only do two damage. The Decimator similarly only does one damage, and I sacrifice it to do a crit. Another command pod casualties. Tycho is used to eat this stress again. He truly has no soul. I stress Corran.
Sixth Turn:
At this point I'm feeling rather nervous. Rexlar is still untouched with his SD but is very out of position. I'm going to have to one turn him and stress to get in the fight next turn. The Rebels are all converging on Whisper, so she must do one damage. After PS 10 Corran fires on me with an Etahn crit. I wasn't looking forward to those two green dice.
Except that never happens.
The transport accidentally runs over a B-wing while turning and takes one damage off the roadkill. It dies. Game over. Rebel incompetence at its finest. The Empire is victorious.


After thoughts:
My MVP was without a doubt the Decimator. I used almost all its hull on Vader crits, and it was the only ship to do good damage to two transports. My decision to reprioritize him against the left transport probably won me the game.
Comms booster is a very good card. It allows a transport to clear stress and give a ship an action. My opponents put it on every transport, and it proved its worth. The Bs and Etahn were almost never stressed.
Rexlar with fleet officer support is fantastic. I used his ability three times and he is almost single-handedly responsible for the death of the right transport.
Ignore the escort, unless there's something that's preventing you from doing damage to the transports. You are likely to be outgunned even with the points advantage.
The transports pack some nasty abilities that will screw with your plans. Jan Dodonna in particular. He causes a friendly ship firing at range one to change a hit to a crit. Didn't do much to me this game, but could be very powerful. Also fear Toryn Far. My opponents didn't run her, but she will ruin your day if she pulls off her ability.
As a Rebel player, stay closer to your transports. Whisper and the Patrol Leader had free reign back there, and it was one thing that won me the game.
The mission was pretty obviously not designed with Phantoms in mind. Whisper did about 14 damage that game.
That said I lost pretty much all my ships. It was very close, and one more turn on that transport probably would have seen it get to safety. Keep this in mind when designing Imperials for this. HLCs are your friend. You have a lot of ships that can take them.
Other thoughts for Imperial squads I had:
VI Fettigator with three proton bombs
Rhymer with two APTs and opportunist supported by squad leader Vader. Didn't take it because no ATC for Vader yet, and I didn't want to proxy with potential new players.
I had Vessery in this list until fairly late in my design. Decided to scrap him instead for Fel and Mauler. Given their performance, he probably would have been an improvement.
This mission was a lot more fun for me than normal epic games.
Edited by DarkArk