I like the idea of this thread a lot, and I really want to contribute something. So I looked through my folder of art I've done for all my unfinished pictures.. I then stumbled upon this guy. I remember drawing this like 2 years ago (or even longer), and waiting forever to put it up on the computer and then never doing anything with the lines...
I never did finish all of the actual lineart, so the original drawing is in the file on it's own layer, so if you do feel so inclined you may finish them, but the lines I have done are more then enough to make a great looking image (I think). :D It's got a few good details, so I think if you're looking for something to work on for an extended period of time, this would be a good one. :D
I'll post a pic of what I did manage to get done with these lines. :)
(Hopefully 7 or so MB isn't too large of a file for a .psd... Compared to my finished images, it's tiny. lol)