No way that Rondo is going anywhere, unless it's bringing them a top-five type NBA player.
The question here is if they're looking to deal Rondo and Allen for Dwyane Wade. That could be seen as a step up by Boston, and if Miami is not convinced they can keep Wade, then they might do the deal as well. And Wade/Pierce/Garnett make an awfully nice core to build from.
However, if I'm Boston, there's no way I'm dealing either Rondo *OR* Ray Allen. Tony Allen - sure - I could use a nice breakfast sandwich. Not Ray Allen.
I think a lot of people overlook the value of a pure shooter like Allen. Sure, he's getting up there in years, but that shooting form of his isn't going to degrade just because of a couple of years, so I can actually see Allen re-defining himself as a player and actually having an extended career because of it.