I was reading "A bit disappointed..." and I had a thought. No, really. I did.
Would you favor a small, magazine-style softback book detailing iconic locales such as Port Maw, Port Wander and the like? Some maps, some interesting NPC's, some plot hooks for both DH and RT? Inexpensive and produced often enough to slake our bloodthirst for new material?
Sure, sure, there's lots of fan-material on sites like Dark Reign, but quite often I find myself willing to pay for a printed, good-looking sourcebook with higher production values that even if it were full of fan-based material I can wager won't be full of boring crap, as lots of the fan-based material inevitably is. If it's worth doing well, it's worth getting paid for.
One locale I'd like to nominate for detailing is Logan's World from the original Warhammer 40,000:Rogue Trader.
Logan's World is the first port of call in the Lost Worlds Sub-Sector, nestled inside a stable Warp Storm just inside the Eye of Terror not far from the Cadian Gate. Every 8-16 years the Eye "blinks" and travel to and from the Lost Worlds is possible for anywhere between a couple months to two years.
Logan's World is a desert planet with a single large continent, and several islands adrift in a vast methane sea. The primary resource of Logan's World is rare ores, which it trades for just about everything else.
There's one main city, Helsreach, which is essentially a huge Black Market run by various gangs. The gangs are mostly divided by race and function. For instance, the Ork Slaver gang and the HoverBus Gang. The HoverBus Gang runs the armored HoverBuses which ferry miners to the mines and back. Passengers are expected to be armed and participate in the defense of the bus... heh heh! Water is a valuable commodity on Logan's World to the point where they have a Water-Seller's gang which includes fat merchants and hired mercenary bodyguards toting big weapons.
Why would a Rogue Trader go out of his way to risk a trip to Logan's World? Well, for one, it is said that whatever you want, you can find it on Logan's World, up to and including spare parts for a Titan. Anything. Of course, everything has it's price and expect to pay more on Logan's World. Conversely, if a Rogue Trader has a near unique item and wants to offload it with no-questions asked and little chance of Imperial entanglements, Logan's World is the place to find a buyer.
Lord of the Ravenwing riding the last Imperial Jetbike? Nonsense. On Logan's World, you can even buy several different models...
Logan's World is also a haven for a galaxy's worth of riff-raff. Outlaws and fugitives from Tau or Imperial law are abundant. Mercenaries, identified with a white stripe painted over their eyes, crowd street corners and bars. Down the streets of Helsreach, you will find humans, Orks, Eldar, Tau, Kroot, Slaan, Jokero, Ratlings, Ogryn, Zoats...and many other species unheard of...even fabled and mythical Squats can be seen haggling with Gretchen merchants on Logan's World. Chaos is not tolerated as likewise more aggressive species such as Tyrannids, but otherwise they function under a sort of Wild West multiculturalism and what little law there is is rigidly enforced by the Gangs.
As such, many Inquisitors find themselves on Logan's World. Some for decades stalking their quarry. Occasionally, as the Lost Worlds are ostensibly Imperial Planets, a well-connected Inquisitor will bring troops and re-impose Imperial Law upon Helsreach only to leave a month or two later. To stay any longer invites being trapped for at least a decade, which results in a death sentence, as no Imperial Commander is going to trap the number of troops and assets necessary to maintain order when they are so desperately needed on Cadia. The same Warp Storm which keeps the Imperium out protects the Lost Worlds Sector from Chaos...and traps the inhabitants.
Helsreach is located in the middle of the vast central plain of the wasteland that is Logan's World. It's an inverted Hive, meaning that the spire is deep within the cooler depths and well-protected crust of the planet. The farther down one lives the more vast their personal and gang assets are. The real movers and shakers of Logan's World rarely risk leaving the safety and luxury of the Core. Not to mention, it's boiling hot on the surface. The continent is ringed with low-rolling hills and mountains wherein lie the vast Mining complexes. Raiders and Ork Slavers plague the mountain passes and gang encampments are everywhere in the many caves dotting the hills.
Well, that's all I can remember. For more info on Logan's World with pictures etc. check out the original Warhammer 40,000: Rogue Trader!