Now, some of you are familiar with the Via Mini and Nano ITX boards. Nice boards running the Via C3/C7 series processors, 500MHz to 1.5GHz. Mini boards are 6x6 inches square and use "standard" PC components. Nano boards cost nearly twice as much and use laptop components. RAM prices for your desktop DDR2 and laptop SO-DIMM memory is about the same. I'd run the OS off a 4GB CF card connected to the IDE busses that are on both systems. Video is integrated. USB and firewire do also exist depending on the hardware setup. Some 3rd party variants have an expansion bus that can have cards added to give additonal serial ports, LAN ports, even a cardbus CF and PC card dual slot.
To make these things connectable as the core of my MILES2020 design, handling any 802.11g communication, doing video processing from a local camera, providing voice communication, possibly driving a HUD or other video display (wrist mounted map screen?). I planned a lot of this for individual microcontrollers, but some of that processing duty can be offset into an ITX system. Nano boards have a mini-PCI slot, mini have a standard PCI, so cards are available for both.
How to mount it? I figure middle of the back, within a molded case. A LION battery pack would be below it, in a similar protective housing and connected via a cable. A USB microcontroller would provide a link to a CAN bus. The hardwired ethernet connection provides a high bandwidth link to a camera module (maybe the MILES gun main MCU?) if used.
Any other ideas?