On the Big O & Dukes show on 106.7 WJFK today, WEC Featherweight Champion Urijah Faber was asked about BJ Penn's chances of defeating Kimbo Slice in a fight. Faber replied that Penn had a "90% chance" of defeating the EliteXC heavyweight, although one speculates Faber really feels the chances are much higher.
The Penn vs. Slice "fantasy match-up" is the product of UFC President Dana White's comment just prior to EliteXC's debut on CBS. White remarked that BJ Penn could defeat Slice in a MMA bout. The effort of White was to disparage Slice's talent level by suggesting a lightweight fighter in the UFC could defeat a heavyweight fighter in EliteXC (or at least Slice). Faber's corroboration merely adds fuel to the fire.
As for a potential bout with Norifumi Yamamoto, it's the same story: Faber wants it; there are no plans in the works to make it happen.