Hexus had the exclusive look at MSI's Dual-Bridge System a few weeks ago, & now they've got a post up on the official MSI press release.

"MSI DBS (Dual Bridge System) Technology supports dual PCI Express graphics card with PCI Express x16 and PCI Express x2 interface onboard. The PCI Express X2 slot onboard is an open-ended slot for ordinary PCI Express X1, X2 add-on card or PCI Express X16 graphics card population."