Will Meugniot has a rough and rambunctious style that goes well with projects like this. He has found a nice sideline putting pinups, usually of Rainbow on the back of preexisting published original art. I may have helped start this trend by buying an early one which looked like he was trying out ideas. The pin up on the back (or front) of this one is a published pin up from a DNAgents special and had absolutely no bearing on my bidding.
It seems that Rainbow's hair gets huger every time she's drawn. On the cover of the sketchbook he sent as a bonus, her hair barely reaches her tailbone and hangs straight down. We are in a long hair era, except in comic books where pixie cuts,buzz cuts, mohawks and such are all the rage. But even there, they don't sell as pin ups.
It looks kind of rough here close up, but from a distance, it's gorgeous.