Just a hunch...
After reading Ausiello's last nights spoilers, and watching next episode promo, I totally think Huddy sex will happen next episode... maybe at the end. I think they want us to get totally surprised, and that's why they're bringing the Hameron long lost issue back. Nothing Hameron happens in the promo per se. Only Cameron walking near House (nearer than usual), and Cuddy asking the fatal question. But Hameron action? Anywhere!
According to Ausiello, and not with this exact words, Cameron and Chase end things because of Cameron's crush over House. Even if it's true (which I SERIOUSLY doubt), does it mean that House will take the bait? Hell,no! And Cuddy won't allow it either!
I believe sex will occur in episode 21, but that doesn't mean all will be sunshine and flowers between them after they do the deed. BUT it will happen. Besides, we still have that closed set, right?
AND we have two weeks between episode 21 and 22. That could only mean two things:
1) That what happens in episode 21 is too much to digest for only a week of recess, or
2) That they want to left us hanging in the air for two weeks with the episode finale (aka, the sex!).
This is only MY speculation. I hope it's true, and next Monday we can all celebrate and laugh about those crazy Hameron theories. ;)