I posted this fun little thing on reddit a while ago, and I thought of sharing it here: Secret Armada.
Each player creates his fleet, but does not share the list. Upgrade cards are all facedown on a small deck next to the ship they're equipped to.
If you use a card, you immediately reveal it. For example, during turn 3 Imps do a bad attack roll. Imp player reveals his commander: Vader. Then does the Vader reroll. Rebels then reveal Lando, do his thing, and discard him.
Basically, when you have to do something card-related, you reveal the card. It creates some interesting situations.
"Reditect damage to the rear Shields" "Sir, it's not working!" "Sithspit! Those bastards are using Xi7 turbolasers!"
It's great fun, specially combined with Corellian conflict! What did your enemy buy this round? You'll find out when he uses it!
As suggested in the reddit topic: even squadrons or ships could be hidden with a third person helping around, for fairness. Hidden deployments! How many ships did your enemy bring? Hidden squadrons! Is that little Xwing actually Luke? Oh boy, oh boy!