I suggested this before, but with a Shuttle nForce2 board instead of a mini-itx board. These boards are only 7"x7" so they are plenty small for just about any two-player control panel. They also have decent onboard video (GeForce 4 family), superb onboard sound, TV-Out, and can accept processors at least as fast as an Athlon XP 3000+. Granted, you don't need that kind of power for Mame, but you can also, of course just pop in an Athlon XP 1800+ which is a great, inexpensive chip that will play everything full speed and still give you decent framerates in Windows games. Those boards, by the way, also have onboard ethernet, firewire, usb 2.0 and have 1 each of AGP and PCI.