Combining Mini-Mate style figures with Lego-like blocks, Stackdown is a brand new line from The Bridge Direct (The Hobbit) which, right out of the gate, seems to be trying for a seriously comprehensive roster.
In addition to the obvious wrestling ring playsets, the line will feature a gym, a production truck, a dungeon for the Undertaker and Kane, and several mini-dioramas that match the personalities - a classroom for Damien Sandow, a hot-rod garage for John Cena, etc. This is probably to circumvent rules that would make them violate the Mattel license for Rumblers - like licensed Lego minifgs, I'd bet they have to be sold with some sort of playset/vehicle, no matter how small, so as not to be called action figures. But they've also given us something Mattel never has, already...a proper referee!
Wrestlingfigs.com has a lot more pics. I will not be getting into these, but they do look fun.