During one of my recent wandering on the tubes, I came across a site called The Monster Engine where the artist started off with the children's drawings and then add light and shadow, depth and shading, all the while retaining all the physics-defying, physiology-stretching, lack of reality from the original drawing.
The results are highly disturbing, and from a D&D point of view, look like something right out of the Far Realm. I could easily see the "finished" creatures being stat'ed up as something truly bizare, like something from Raistlin's Lair of the Live Ones (see Jeff Easley's painting here).
Alternately, I could see a modern horror game centering around the original children's drawings, only for the heroes/investigators to confront the manifestations of those drawings (and showing the finished art for that reference).
Either way, I highly encourage you to check out the The Monster Engine.