I came across this site today, and I’m loving it! It’s a collection of “What if?” movie posters by Peter Stults; taking films we know and (mostly) love and turning them on their heads with new actors, directors, time periods, and of course wonderfully retro movie posters. Here are just two– there are tons more on the site, and some of them are available for sale as prints! I might just get the Fritz Lang “2001: Odyssee Im Weltraum” poster if it was available.
Excellent posters! On a related note, you should take a look at the following link. It's a "what if Raiders of the Lost Ark had been made in the 50s".
http://www.youtube.com/watch?v=GUPDuQq9GsM
Ha! That was excellent, Hugo.