I'm not quite sure if this counts or not, but I would think it does.
I just got Pocketbike Racer and I went to add it to my library. It has two listings for the same game. One for original XBox, and another for XBox 360. Except there aren't two separate releases. It's the same release, and it works on both consoles. But wouldn't that just make it a backwards compatible original XBox game? The artwork, admittedly, does deceiving look like an XBox 360 game, though.
XBox (original) entry:
http://vgcollect.com/item/59763
XBox 360 entry:
http://vgcollect.com/item/11186