On his radio show last night (subscription required and recommended), Dave Meltzer said Dana White wants the Lyoto Machida vs. Mauricio "Shogun" Rua rematch on UFC 108. Meltzer also stated that Shogun has agreed to the date, and Machida will let them know if he's healthy enough to take it.
They want to return quickly with Machida/Shogun because the controversy is hot right now and if they can make a rematch announcement soon, they can assuage fan anger and channel it into PPV buys. If UFC 108 has Lesnar-Carwin, Machida-Shogun, and Evans-Silva, the show should break the million buy mark.
They won't do Lesnar-Carwin, Machida-Shogun, and Anderson-Vitor on the same card, because they'd have almost nothing for their shows at the beginning of next year, and they won't overload New Year's.
It may be a mistake for Machida to take a rematch so soon. There's just no way he can get a full training camp in given the beating he took Saturday night and the time he'll need to recover before he can train at full speed.
This is a good example of a situation where what is best for business diverges from what is best for the sport. The best thing for business is to put this rematch on as soon as possible to strike while the iron's hot. But at the same time, I don't think anyone wants to see Machida lose because he's injured and unable to train. I think the best course of action is to do Lesnar-Carwin and Sliva-Belfort on this show, and delay Shogun-Machida until the Superbowl show.