You know, I've been sitting around for a long time wracking my brain trying to figure out why nobody has done this before... but I think this would make an excellent game:
A combination of sandbox industry building of X2/X3, gameplay like that of the X-Wing series, and vehicle use the like of GTA or a Battlefield/Battlefront game, and strategic elements the like of Battlestations Midway to create a sandbox Star Wars sim.
Actually, come to think of it... it'd be very much like Star Wars Galaxies. Except, you know, GOOD. And single-player. Oh and good.
Imagine... a sandbox game where you can explore the SW universe, build a trading company or become a pirate, join one of the factions in the GCW, land on and explore space stations and planets (they don't have to be box-o-crazy big, the ability alone would be worth it). Eventual ownership/command of capital ships with the ability to strategically command fleets in battle.
I know, this would be one hell of a coding job... but I would seriously pay $100, maybe more for a good title, for something like this.
We can dream, I suppose.