There are a couple droid PCs around, you can pretty much use anything really, I would love to see someone make an astromech PC. That'd be boss.
Everyone knows astromechs are just a bunch of potty mouthed trash cans. Here are some droid PCs. http://www.thestarwarsrp.com/forum/index.php?threads/r0o1juivqz-roo.74195/ http://www.thestarwarsrp.com/forum/index.php?threads/5r33-y.73053/#post-1350045 http://www.thestarwarsrp.com/forum/index.php?threads/x3r.69803/
Not sure, though I'd go so far as to say B1s would be rather generic, so you could always as if you could RP as one but under a different name, so not a B1 but still a B1.
So...Could I be something that looks and acts like a B1, but exclude the whole separtist alliance and trade federation nonsense?