I've heard rumors from people with no connection to anything (read: pure speculation from my mailman) that the UFC will push for a Brock Lesnar vs. Fedor Emelianenko fight at UFC 100.
That won't happen, because it will be too soon after Lesnar's win over Nogueira, but now that Couture has been taken out of the equation as a top heavyweight, the natural assumption is to speculate on Lesnar's chances against the top heavyweight in the world.
I doubt UFC president Dana White will sign Fedor because he won't have control of him like he does Lesnar. It doesn't do White any good to have Fedor come in for one fight and possibly take his heavyweight championship before fading away again. Lesnar has nowhere to go, as he rakes in big-time cash, including a percentage of pay-per-view buys and money from merchandising and action figures.
Still, MMA fans can dream. Could Brock Lesnar defeat Fedor?
No. At least not at this point. That being said, Lesnar's size and athleticism make me believe he could give Fedor the best fight. Fedor will demolish Andrei Arlovski when the two meet (Arlovski hasn't done anything to impress in a long time) and would do the same to Josh Barnett.
Lesnar's aggressiveness and excellent wrestling could at least make things interesting, potentially ... maybe ... possibly.
I think Fedor would submit Lesnar but it could be interesting. However, I don't think we will ever see it.