Engadget has a picture of MSI's Big Bang Marshal, a forthcoming XL-ATX motherboard that features eight PCI Express
x16 slots, eight USB 3.0 ports and three BIOS chips! The motherboard is expected in Q1 2011 but the site notes the specifications are still subject to change, perhaps the final edition will have room for more DIMMs.
This XL-ATX board packs a total of eight PCI Express lanes (though it only has the bandwidth to simultaneously feed four x16s or eight x8s -- relevant if you're crazy enough to think about using more than four GPUs), three separate BIOS chips, extra 8-pin and 6-pin 12V power intakes, and a thoroughly excessive set of power regulation components. The less extremely minded among you will appreciate having a full array of eight USB 3.0 ports on the back, though we can't get over the measly four DIMM slots on offer.