KhoipandaI don't know about further expansions; I'm grabbing it for the minis. Prepaints are expensive, and these look pretty good. You can use the miniatures for plenty of other games (Pathfinder, D&D, whatever).
KhoipandaDouble-check on BoardGameGeek, but MK:R was released in 2013, and I didn't find any expansions, so I think it's dead. If you're in the SF Bay Area, I have some MK 1.0 figures, but I think they're incompatible with MK:R. Look me up as "Sam and Max" on BGG. If you're looking for prepaints, also see the upcoming Reaper Legendary Encounters KickStarter this fall!
EDIT: Cardhaus and CoolStuffInc (only singles) no longer carry this, and Miniature Market sells it at MSRP (or at least not as good as a discount). So if you're looking for this particular game, it's a great deal.
EDIT EDIT: Shipping didn't increase much when I went from 1 to 2 quantity, so buy a second set!