QME makes you able to switch between ATX and Mini ATX form format. If you switch to ATX you will get 2 additional SATA ports to use, and 2 extra PCI slots.
Akiba found this motherboard for 25 750 Yen this is about $217.
QDI P4I875P Mainboard Specifications:
• CPU:400/533/800MHz FSB,Supports Hyper-Threading and Prescott CPUs (>3.06GHz)
• Chipset: i875P/ICH5(R)
• Memory: 4 DIMM sockets, Dual Channel DDR333/400
• Expansion Slots: 3 PCIs (supports up to 5 PCIs with QME technology), 1 AGP 8X
• Hard disk: 2 Serial ATA150 (supports 4 Serial ATA with QME technology)
• USB:6 USB 2.0 interfaces
• LAN:Built-in 1G Ethernet LAN
• Audio: 6-Channel AC’ 97
Source : Akiba