Assuming Rampage beats Jardine and gets the first shot against Rashad, Lyoto will almost certainly have one more fight before his shot. Now that he's had that breakthrough finish, it's time to give him a big fight. Here are some options:
Forrest Griffin: Griffin returns this summer if his injury heals correctly, and this would be a natural number one contender's match. The downside for UFC is putting Griffin in this position when he's such a popular star and they likely want to rebuild him after a loss.
Rich Franklin: Rich is coming off the close loss, but there's a natural story since Machida beat him once. I don't think Rich wants this fight, I don't see it happening.
Chuck Liddell: I think this is the best choice. Assuming Liddell wins against Shogun, this can be a contender's fight. If Machida finishes Liddell it will cement his place among UFC fans, and if Liddell finds a way to beat Lyoto he will vault himself right back to the top at 205. I don't know if Chuck would want it, but giving him a chance to get a title shot faster might be enough to get him to bite.
Randy Couture: This is a longshot, I am only including it because I heard Couture has expressed interest in trying to find a way to beat Machida. He wants "interesting fights," and this would be the pinnacle of that. I honestly think this is a better use of Randy than a match with Nog or Mir, and much more interesting as a fight. Unfortunately, I think it's unlikely.
Jon Jones: Ok, so this is highly unlikely, but I must include him given my Jon Jones fandom. I want to see him suplex Lyoto, and at least we'd be guaranteed an entertaining fight.
Brandon Vera: Assuming Vera is able to beat Mike Pratt, the timing would be about right. I can't help but thinking this would be incredibly boring though.
Overall, I think the best choices are Chuck and Randy. If he's not getting a shot, it's time to at least give him the kind of fight that will make fans clamor for his shot if he wins. Of course, all this goes out the window if Rampage loses, but I already assumed that possibility away.