One phrase recently used to find my blog: "using dinosaur swamp with mutant future."
I've actually thought about such a project in the past. The PCs would probably be lost Coalition personnel, stranded in Dino Swamp after a mission gone wrong. Dinosaurs and lots of big lasers and rockets to shoot them with, and no pesky ass tour guide telling you to get back on the metal path.
It might be a fun thing to run over Winter Break...if any of my local gamers have some time off during the day. (Dan, Mike...looking at y'all)
I'll always stick to my (mega-damage) guns that RIFTS books make better source books for games other than RIFTS.