The Flickr group Wasn't the Future Wonderful? has some great examples of postmodern paleo-future art. These pieces co-opt and remix past visions of the future, giving an interesting context to current visions of the future.
Kozmonaut by ART NAHPRO
eye lines by Nesster
Moonweb by Matt West
Au Revoir Planet Earth by Mattijn
Soon Mariska, Soon by john_bolin2002