Last week, speculation surrounding a pending announcement of the oft-rumored, slimmed down "Valhalla" model of the Xbox 360 was kicked into high gear, thanks to a Microsoft hiring notice for a motherboard engineer, and Steve Ballmer's reference to "more form factors" for the hardware. Earlier today, a Chinese tech forum purportedly posted a pair of pictures of the newly remodeled motherboard, which has undergone a massive size reduction from the current iteration of Xbox 360 hardware.

A few noteworthy changes in the motherboard (full pictures of which can be found after the jump) are a consolidated GPU/CPU, an extra SATA port, and a much smaller heatsink. Though the design could just be a mock-up from an extraordinarily talented modder, it certainly looks like professional-quality work. We've contacted Microsoft to see if they'll comment on the skinny-fied hardware.