docwyte

There are quite a few actually. Off the top of my head, Boost Creep has one, MAC (now MoFab has one) and there are several others. Too many Subaru's and Evo's out here for shops to only have a 2wd dyno...

pfbz

My understanding is that you don't just need any type of AWD dyno, you need one with "linked" rollers (if you want to run in AWD mode) that will keep the front and rear rollers at the exact same speed, simulating a fixed surface under the wheels. And these are pretty uncommon...

Without a linked AWD dyno, and with the front driveshaft in place, I think you put your center diff at risk for damage.