okay, another update.... first of all I got the Micro-ATX board. Real nice board. Yeah, it's bigger than the VIA MII, but it's much faster. It does indeed support high-speed USB booting. Only problem is that the BIOS sees the uDOC as a floppy disk type device instead of a harddrive which screws up the XP boot up process. No matter what arcpath I've given it, it can't boot up. If I format the uDOC in DOS then I can boot up as if it were a floppy disk, but since you can't run fdisk on it you can't create an active partition. You're actually supposed to use an M-Systems native XP tool to partition and format the uDOC for FAT32, NTFS, or NTFS Compressed. But the BIOS configuring it as a floppy screws up NTLDR probably. I'm waiting to hear back from Intel about this. Most new BIOS's let you configure how you want removable drives to show up (floppy, hard drive, cd, etc.). What I'm thinking is happening is that the BIOS assumes the uDOC is a floppy based on its size because my 1GB CF cards show up as hard drives over USB. On a side note, yes high-speed booting really is fast. Just as a test I booted using one of my CF cards on a USB card reader and it was damn quick. I'll post more when I hear something from Intel.
Also, it seems the ExtremeIII boots one or two seconds faster on this board than it did on the MII, so if all else fails I can still use the CF disk.