A Star Wars complete conversion mod would be really cool. There's plenty of images for Star Wars spaceships out there, too. I might try working on a star Wars mod once I finish the one I'm currently working on, but perhaps some other guy could make one instead?
I guess it depends on what your quests look like, and how involved you want to get with making them ship-specific. I would suspect that you'd be able to work out something with each type of ship. You could even do a medical frigate (although I'm not sure how distinct it would be when viewed from above) and then have a bunch of medical quests for it. Bounty hunter is a good one too, and you've got a while mess of bounty hunters to choose from in the movies.
I'll second the bountyhunter idea. It'd be cool to pilot or fight against Slave I.
(Originally I was going to suggest an Imperial Interdictor-class cruiser, but I can't think of a way to do it justice that wouldn't shoot down all missiles and/or make the Temporal Flux shield less cool.)