Tried this once...
on 12-21-2009 12:07 PM
I tried this a few months ago - I unwrapped a character in 3DS using the checker texture, then rendered a UV template with white edges and black background. In Photoshop I inverted this to get black edges and a white background. I then lightened it with Levels and printed it off at 7" x 7" which interestingly enough comes back in right at 512 x 512 when scanned.
Anyway, I only did line drawing/inking on the printout, scanned it back in, and did the coloring in Photoshop. As was stated by Swizzle in another post in this thread, it didn't work out so well because of all of the trial/error involved in getting details placed just-so on your UV layout. When you create texture details in Photoshop you have the layers to move stuff around, but when you draw it by hand, you're stuck with it unless you want to draw it again. Of course, you could resort to some of the rapid viz/technical illustration techniques of iterative drawing using tracing paper... but now you're talking about an enourmous effort for something that can probably be emulated with a good stylus/tablet or some creative use of Photoshop filters.
Bottom line is - yes, it can be done, and with appropriate planning and patience, it can be done well. But personally, I'd rather hit myself in the head with a hammer 5 or 6 times.