Decided to pull up this old thread and add a few more. Some of these are Bendo's suggestions and others' are my own.
Dominick Cruz *New* - Quicksilver Pretty self explanatory.
Ben Henderson *New* - Shatterstar (self proclaimed)
He was genetically engineered to have enhanced physical capabilities so he could serve as an arena gladiator.
Shatterstar learned the arts of battle as a warrior in arenas on Mojoworld, where he participated in combats staged for Mojo's television programs. It’s assumed it was here he developed his strong sense of honor and pride as a warrior, to combat the constant violence and death in his life.
Jon Jones - Green Lantern
Artists in combat, these figures facilitate the destruction of their opponents through imagination and creativity. Jones uses brutal takedowns, spinning back elbows and high kicks; the Green Lantern’s power ring can do virtually anything. But with no jewelry allowed in the Octagon, point Jones.
A combination of Stretch Armstrong and Robot Chicken *new* - Well you figure it out.
Junior Dos Santos - The Silver Surfer
The Silver Surfer’s sleek bald head used to be an omen that an evil God-like villain, Galactus, was about to eat your planet. Nowadays, it’s Cigano’s sleek bald head it’s that signifies imminent vicious punching power that will destroy your world. Hyperbole is disproven by his UFC record: four knockouts in the first round and one man-handling of Mirko “Cro Cop” is not hyperbolic.
*New* - Colossus - Goofy nice guy who speaks in a foreign accent. Then changes once he gets into the Octagon then he turns into a powerful fighter.
Chael Sonnen - Banshee
Banshee possesses a "sonic scream," capable of harming enemies’ auditory systems and causing physical vibrations. He is named after the banshee, a legendary ghost from Irish mythology, said to possess a powerful cry, although the banshee spirit is invariably female and the Irish Gaelic to English translation of Bean Sidhe (Banshee) is literally Fairy Woman, making it an odd choice for a male character (the male version is Fear Sidhe). Nonetheless a fitting name for the mouth of West Linn, Oregon.
BJ Penn - Cabbage Patch Kid
Cute and cuddly. Posesses a perfectly spherical round head near impervious to wound.
Roy Nelson - Most would say Kung Fu Panda, but today I'm leaning towards Nacho Libre.
Chancho. When you are a man, sometimes you wear stretchy pants in your room. It's for fun.
Anderson "The Spider" Silva - You guessed it. Peter Parker.
Why, cuz in his own words he's the only super hero with bills to pay...haha! Oh and inside the Octagon he weaves traps and ensnares his opponents.
Got some suggestions. Feel free to add to the list...
Marcus Aurelius: Tell me again, Maximus, why are we here?
Maximus: For the glory of the Empire, sire.
Baked, not fried... the healthy choice.