building small, low spec, machines

(Cross posted, follow ups set to achp-h)

I like the small size, and reduced functionality, of computers such as the
ASUS eee pc. That's the kind of size, price and power that I'm after.


How easy would it be to build a small machine - not necessarily in a laptop
case - with similar size and specs.

Mini ITX is small enough. The VIA motherboard EPIA-5000AG seems to be
okay. It has 4 USB sockets, onboard graphics and audio, onboard lan, and
is fanless.
<http://www.itx-warehouse.co.uk/Product.aspx?ProductID=654>

I'm having real trouble finding small displays at a sensible price. has
anyone seen people using, for example, picture frame displays for a project
like this?

I'm also worried about the practicality of using batteries for this, so I
might not do that, but use a power cord.