I thought the Paleo's ate Wooly Mammoths, tree moss, a lot of pleistocenes and stuff like that. They were more "gatherer-hunters" than "hunter-gatherers," by the way.
You gotta go gather and hunt your own stuff, right? Or it doesn't count? Sounds like a long term camping trip to me, which could be fun after a couple years. What did they make Gatorade out of, saber-tooth tiger gland extract? Did they have falcons to hunt with in Paleo-ville? I don't know.
But I agree with the thread title. No, I don't think it would be a good diet for ultra-running, more like something to boast about at a party (drinking only grog fermented in a hole in a rock, of course).