RYNO Motors' single-wheeled electric scooter is self-balancing, has a turning radius of zero when stopped, and only takes up about as much space as a folding bicycle -- so it's conceivable that commuters could bring one onto a train. Plus, it looks like it fell out of a Japanese anime.
2006 Suzuki GSXR 600!!! Matte/Flat black paint job w/ hot pink powder coated wheels and triple tree. Had one red & black...didn't scream girl bike though. Liked the reaction when people found out it was a WOMAN ridin it.