Spendios, that was a great idea, and I'm in a crafty mood, so here's what I did this afternoon:
(this post) Ground Sloth
Suggested stats: Hp. 24 Siz. 4 Str 24 Att. 14 (ambi), Def. 12, Prot. 6, Mor. 14 MR. 10 Mv. 9/1 Prec. 6. Forestwalk. Weapons: Claw/Claw. Poison cloud (weak). Animal.
Note, while the images themselves are not 100% original, some of them are free (from Wikipedia) and they have all been extensively modified, to the point where there should be no copyright worries.
The beetle posted earlier was all mine though
Feel free to use them however you want. They're not game-ready, but they should give quite a head-start for anyone interested in adding prehistoric animals to the game.