I like watching Thompson, actually. I thought he did do well enough (compared to most who have been trying) in the first fight with Volo and I think his chances vs Stiverne wouldn't be too bad at all. He did very well for himself considering starting boxing in his late twenties, getting a title shot twice and giving Klitschko a decent fight in the first. He's still a top 20 heavy, as far as I'm concerned, but he doesn't have it in him to challenge Vitali Klitschko either or Haye, I don't think. So, that's the top three guys out, in my opinion.
He can't pull the trigger fast enough without getting hammered against these guys. If I were him, I'd try it on the just "name fighter" circuit where he can make money and likely win against other guys who still hover in the top 15-30 guys. Guys like Peter, Grant, Mormeck, Charr (shortly), Walker, maybe a Banks fight could be set up well. He can still have a few fairly good smaller fights. He won't be winning any titles though. Unless it's off of Holyfield or Toney. But, really, even then, that would be a nice thing for his career. Parting gift matches against other guys in their forties.