Huh. Tried posting this response before, but Jerbo apparently ate my post.

I frickin love GURPS Ice Age supplement. But never have run it for two reasons:

1. After years of consideration I've come to the conclusion that I just don't particularly like GURPS as a system.
2. I can never think of stone age scenarios that feel compelling in my mind. Not sure what quality would quite seem satisfying.

But still have some fascination with a dawn of humanity type setting.