Quite awhile ago, Bruce wrote to tell me about two comic-themed mosaics he posted to his Comic Bricks blog. Here they are:
First, there is War Machine from Iron Man, made by Adam Myers (getdamonkey_):
And secondly, here is the Joker, by Brian Hanna (BrianTheLegoNut):
Looking at Brian's photostream, I see he has made quite a few other LEGO mosaics as well. Check them out here.