Here is a barebone kit for $262.00 that supports windows installation, If you were to vaccuform your own case you could knock a few inches off of the height, and perhaps the width and length too. I think this computer is adorable, if your have cargo shorts it should fit in the pocket as is. It uses a Pico ITX Motherboard. Which in your first post I noticed that you mentioned something about Pico projector, fairly certain this is not the same as what you were speaking of. Also this has 2 usb ports for extra accessories. And you could probably hook up a 3g or 4g wireless card for on the go. As far as power goes you maybe able to hook up some sort of battery and a solar panel for it.
http://store.viatech.com/protected/prod ... on?id=9262
I think i like this company seems pretty cool heres a quad core system with the same size board for $359.00, No case it seems though. Or ram, or hard drive included.
http://store.viatech.com/protected/prod ... on?id=9621
Here is an 8 gb ram card for $40.99 for the system only has one ram slot
http://www.newegg.com/Product/Product.a ... 0ST08P6207
Here are the specs, Pico-ITX board with 1.0GHz VIA QuadCore E processor with 1 x LVDS, 1 x VGA, 2 x SATA, 1 x Mini-HDMI, 2 x USB 3.0, 6 x USB 2.0, 1 x GigaLAN, 12V DC-in
That has plenty of accessory ports for any item you could think to plug in.
Compact 10cm x 7.2cm Pico-ITX form factor
High-performance 64-bit VIA QuadCore E-Series processor
Latest VIA VX11H media system processor with DirectX11 support
Flawless 3D and HD video performance up to 1080p
Supports 2 USB 3.0 and 6 USB 2.0 ports
HDMI, VGA and one single-channel 24-bit LVDS support
Supports high-bandwidth DDR3 1333MHz memory, up to 8GB
Support for two SATA
HD audio support
Supports digital I/O