I have a broken nano and a mostly working nano.
The broken one is 4gb, black, and the following parts are confirmed broken: the screen, the scrollwheel, the board. the following parts are presumed working: the flash memory chip, the battery, the case.
The mostly working one is 2gb, black, and it works fine until you bend or torque it in a certain way, at which point it will cut out and die, and require restarting. I've tried touching up parts with a soldering iron, I've tried insulating it in electrical tape, I've tried adding spacers in it, but no matter what, if you grab it by the sides and bend it in a certain way, it will shut off. Occasionally when you plug it in it will say "battery critically low" and not accept a charge, unplugging it and plugging it back in fixes that.
I'd sell the broken one for $10, and the (mostly) working one for $50. (plus shipping from canada)