MacBidoulle posted images claiming to be of the new PowerMacs. The design is also detailed by this PDF. (removed per Apple)
Further comments provided by the author of the PDF posted in this MacRumors thread
Previously submitted details from the PDF author:
- the heatsink is a very large aluminum straight finned squared design. about 6" x 7" x 6" approx and weighs about 7 lbs; it is attatched to the MLB by 3 screws, but not like XSERVE; 2 screws are on countersunk standoffs that go through the MPU, and one that attatches to the back panel on a ridge above the modem port. The MPU itself is held down only by the weight of the heatsink, and a 'flex' bar, that is a plastic bar with 2 metal springloaded clips that allow it to flex freely.
- the door mechanism has been totally redesigned, instead of plastic hooks, it is all metal. Only the round hole handle is plastic, which actuates metal u-shaped hooks which slide in and catch; very smooth, no more slamming closed; and nearly impossible to break open with lock, metal on metal.
- the modem stays the same but in new location.
- the 4 decorative holes in the front are for show, but also allow air intake for the 'turbine' fan sitting in front of teh heatsink (with door closed), the turbine fan speeds up and slows down depending on tempurature. An extra fan in the door ventilates the MLB and dual CD drives (vents galore).
- BlueTooth will NOT be included, it will be as is now, a USB addon
The motherboard design appears similar to the prototype motherboard leaked on eBay.
Update: A previously accurate MacRumors source provides some independent confirmation of the case design: Yes, the enclosure seen on that PDF is real.