Mark Gurman, on the smaller Mac Pro:
The second version, however, will use Apple’s own processors and be less than half the size of the current Mac Pro. The design will feature a mostly aluminum exterior and could invoke nostalgia for the Power Mac G4 Cube, a short-lived smaller version of the Power Mac, an earlier iteration of the Mac Pro.
It’s just a rumor. And there isn’t much to go on aside from it being smaller than the current Mac Pro. But if it’s also lower cost — in the realm of the entry-level 2010-era Mac Pro — I’m going to be very interested.