I'll see if I can get you to the WOTC checklist so you can see what the Rares and Very Rares are for the current set. I assume your talking about the ROTS minis, right?
As for what's up next, that would be the "Universe" set, which includes "Huge" minis like the Rancor, AT-ST, etc, and figures from the entire Saga and the EU. Can't recall when that's due out, but it might be within the next month here.
I'm also going to merge your post in with the rest of the WOTC miniatures discussion that we have somewhere in here too. Though the discussion on this line has tailed off here a little bit of late, you'll probably find some other good info in the rest of that thread. So stay tuned for the merge in a few minutes here...
(whoops, I see one of our other mods is way ahead of me on the merge there)