To be honest, most fundies do acknowledge that dinosaurs really existed. Very few actually deny that the animals themselves were real.
However, that is about as reasonable as they're going to get, and shoehorning the existence of dinosaurs and other prehistoric creatures into their worldview has resulted in the following bizarre ideas (which vary depending on the particular fundie you talk to):
Claiming that dinosaurs, like everything else, were created 6000 years ago and therefore coexisted with the earliest humans.
Claiming that dinosaurs were merely modern reptiles that grew to huge sizes before the Flood (modern reptiles never stop growing, you see, and people lived to be 900 years old then, so...)
Claiming that Behemoth and Leviathan in the Book of Job were a sauropod and a pliosaur, respectively.
Claiming that the various mythical monsters (especially dragons) described in different cultures' traditions were inspired by encounters with dinosaurs in the distant past.
As for the "T. rex ate plants" thing, young-earth creationists actually believe ALL animals were herbivores before the Fall of Man.
EDIT: SpaceProg, I agree as both a Christian and a paleontologist.
