The greatest part about the vehicles in Star Wars is how diverse they are. An X-Wing is a completely different design philosophy to a tie fighter, both in form and function. A B-Wing is even more different, with the rotating cockpit and unique appearance. Which I think slightly resembles a killer bee about to sting, with the main cannon on the bottom wing as the stinger, the other wings as the wings etc. Hence, Bee-Wing.
that or, apparently, Lucas wanted more ship designs to diversify the battle above endor and distinguish it from the battle above Yavin. The concept art was turned in, titled "design A" and "design B' and apparently stuck which fit the A-wing nicely but left viewers scratching their heads at the T-looking B-wing
I still like my crazy theory, even though we don't know how bees look or behave, or are named, in the Star Wars universe.