While the others are actually working on this, I'll just be writing a blog post, because the question has come up often enough these days :

Q: When will Gnome 2.22 be available in portage ?

A:

<dang>The mask is in place, and a few packages have been brought over.
<leio> When it's ready. We are working on moving it to portage right now. So, say, in 2-3 days is realistic for unmasking - no promises.

There, now y'all know.