This concept interests me because I'm thinking of putting together such a thing, and thanks to the astonishing number of PD images available, mostly on this site, and a clever little app called Photoshop, it sounds as though it ought to be fairly easy. Yet I haven't seen that many attempts to do it, and nearly all of them do what Seanbaby over on Cracked does - use the original comic totally unaltered apart from rewriting the speech bubbles, usually to make a not very original point, such as: Aquaman's a waste of space, Robin looks a bit gay, and fighting crime by dressing up as an old lady isn't really all that plausible.
In fact, I've only seen one serious attempt to write a totally new ongoing tale by collaging elements from multiple GA comics in a new and interesting way, and that was a dismal failure due to a horribly ill-advised storyline. Which is odd, because 80 years ago Max Ernst arguably invented the graphic novel by cutting up and recombining artwork from sensational 19th-century literature in his groundbreaking and still influential trilogy of "collage novels", so it's not exactly a new idea.
So, two questions. Firstly, has such a thing been done successfully already, and I've missed it because if I tried to check out every webcomic in existence, I'd spend the next few centuries looking at a zillion pages of 99.99% dreck?
And secondly, are there any comics in your database which would particularly lend themselves to this kind of treatment? Bonus points would include especially good artwork and high-quality printing with vivid colour, unusually detailed and/or bizarre imagery, clearly defined people, objects, creatures, etc. that can easily be snipped out, an artist who really knows how to draw people with interestingly varied poses and expressions, and ideally a few long-running series either about obscure non-costumed heroes whom nobody will recognise, or featuring such people in the supporting cast, so that I can rename them and use them as my major characters. If a good artist habitually draws very similar-looking people in unconnected stories, that would work just as well.
Suggestions, anybody...?