Than Chael vs. Forrest. More compelling and would put him in contention with a win.
I do believe Machida would demolish him though. 
i would pick him fighting forrest. there is a chance of him winning that fight. it could end up being a good match. him vs machida would just be a nightmare for him. he can't take him down so he really has no chance
The problem is the UFC wants him to win. This fight would be big (Jones has talked a lot of trash on Machida and I'm sure he'll continue to do so, and Machida is coming off a huge performance on Fox) and the UFC knows that, but they don't want Chael losing. 
Unfortunately I think the UFC knows that Machida would put Sonnen in a body bag.
Machida would embarrass him, kill any more money they can squeeze out of Sonnen with other fights, and the win really doesn't do much good for him.
Though I would watch for the lulz. Don't get me wrong.
Chael Sonnen using his persuasive trash talk like a boss.
Machida would hurt him bad though.
Makes sense