I too have an older bike (i.e., late 70's Mino Denti) thats paint job is far, far away from what it must have looked like when it was first created. Thus I too have been Googling around trying to find out what other folks say about repainting a "classic". I guess the real deal, beyond the concern of devaluation, is whether or not you'll feel better or worse looking at it, riding it, etc.

For me, I know I will never get rid of my bike so I don't care about the value part. I just love it. I even love the way it looks with its messed up scratched up paint job (i.e., battle scares). Thus, hmm, I guess it's what they say, "beauty is in the eye of the beholder" and therefore I suggest, if you're not worried about devaluation, do or don't do whatever it takes to make you *feel* the best about your bike.

Hope this helps!