Small computer to run a GUI?

[John Levine]

>I was more thinking of something without a monitor, keyboard or mouse. I
>want to put it in a cupboard and not worry about it.

Sounds like a Soekris.  Their net5501 has a 500MHz CPU, 512MB RAM,
serial ports, Ethernet, USB, compact flash, SATA, mini-PCI, and no video.
It runs FreeBSD.  The case is quite small, 6.7" x 11.5" x 1.3", but
has room for a 2" SATA disk if you want to add one.  If you want wifi
you can plug in a mini-PCI card.

They make it quite clear that their market is OEMs and they do not
offer software support, although there is a friendly community that is
helpful if you ask sensible questions.  Many people run FreeBSD on them.

With a case and wall wart it's under $300.  They have slower cheaper
boards, if that's all you need.

See http://www.soekris.com/net5501.htm

R's,
John