Dino Hunt is exactly what the title says: a set of dinosaur hunting rules for 25mm – 28mm figures. Some of the dinos in that scale have to be huge.
Big Game Hunt is a game of dinosaur hunting. Really.
Fans of Lost World type games may be interested in some harticles on the Cryptomundo site that sow early 20th century newspaper stories on the search for the Mokele-mbembe, a dinosaur-like creature thought by some to still be alive in Africa. You can also look at the articles in a pdf format.
Of course no one knows exactly what a dinosaur looked like, but Andrew Thompson will tell you how he painted a very nice looking one for his land that time forgot miniature wargame.
Dinosaur Cowboys is a set of role playing / miniatures rules that reminds me of the old comic Cadillacs and Dinosaurs. It looks like a lot of fun.