I liked a birkin that was on eBay with indigo outside and blue jean inside. It also had blue jean piping, which I don't like so much. I also saw a picture of a black chevre birkin with a raisin interior. GORGEOUS!!!
mightykismet has one on eBay right now that's dark forest green with vert anis piping and interior - its fairly fabulous. But my absolute fav. bi-colour is the black/orange croc.
I saw a 32cm Kelly in the dark forest green with vert anis piping (same as the one mentioned above) at the Hermes store today. I am not a fan of green but this was fabulous. I almost caved in until my hubby snapped me out of it!