Mountain Myst:
I am sure that is quite possible. It is based
on a normal VIA EPIA motherboard and
the CPU, VIA C3, is 100% x86 compatible.
I have 2 of those motheboards myself.
My server is running Win 2000 Server
on EPIA800 and my mediabox 2000 Pro
(EPIA M9000).
For further information about EPIA,
look here
Mini-ITX.