TheSagaContinues

Dare I say selling an ISD would probably be a lot like trying to sell an Aircraft Carrier here on Earth with the added complication that the seller is NOT the legitimate owner.

A spot-on analogy. I'm trying to imagine a group of mercenaries trying to successfully hock an aircraft carrier anywhere on Earth and failing. That kind of "listing" is so far out of the league of even that black market that its jaw-dropping. And the "wrong people" would find out about it really fast.

Frankly the situation you are describing seems like a "galactic-level" event so you aren't likely to find much on it. Three ISDs is enough to make anyone into a warlord capable of holding dozens of star systems. With that kind of firepower, finding a buyer willing to engage with you like a regular merchant is impossible. Buying stolen Imperial warships is tentamount to asking the Empire to attack you, and you can't really hide them. Your asking price is likely to be quite high. So really only military powers could afford to deal with you. But a military power is also more likely to either see you as a threat, so they may just try to overpower you and steal the ships for themselves. Alternatively, they may send highly trained operatives to hijack the vessels (which might be a fun encounter).

If your PCs are really interested in the bottom line, the best bet is to scrap the ISDs and sell the parts all over the outer rim for a great fee. But you will find it won't be easy to find a ruleset that accommodates your PCs if they are free agents with this kind of firepower and cash. 

Dredge finds a shady spot to recline near the trucks and waits. He keeps a cold beverage and his blaster on hand. He will "take 10" on perception checks to notice trouble while he waits.

Perception 10+3=13.

Dredge leans heavily on a wall, unimpressed. "Sick tactics aren't anything new. I've seen govs and rebels alike using disease for hundreds of years. I've been paid by some of them, too.

Dredge turns on the AC.

"This skulking about is a tiresome," Dredge says, pushing past Sin and into the alley. "We should just walk there and get what we want. That's what tired spacers do."

Dredge heaves himself to his feet and plods out of the hangar vicinity and into the street beyond. "Going to get my stuff." the alien mutters to the group as he gets up. "And unless I'm told otherwise I'm going to find a drink after that."

Spoiler (hover to show)

What is this area like? Is it developed or rural? Are the streets crowded or empty?

Seeing the Imps enter the hanger bay, Dredge grunts and makes a show of lifting something heavy. Choosing one at random, the Feeorin steps heavily over to a cargo crate and attempts to pick it up. With a grimace, the alien quickly realizes he might have chosen poorly.

Dredge makes a strength check 1d20(3)+10 = 13.

Dredge elbows his way onto the bridge, seriously decreasing the amount of available walking space. In his left hand he holds an oversized blaster pistol that still somehow appears diminutive in his massive grip. "Boarding party isn't a problem. If we can't trick 'em, we take 'em. The big ships are harder."