OK, so I finally got the scoop on the Parnassus poster from IMP (David):
"I contacted the designers of the poster and they just replied with the following: '...sadly I don't really know where they ended up. There was a print run of just 500, a few of which we kept here for our files, and all of the others went straight to Terry Gilliam's daughter! I really have no idea what she did with them, or if they were just giveaways in the end.' Sounds like it might be near impossible to get a hold of one of the originals. Anyway, I hope that sheds a little light on things."
