Re: Need help purchasing/creating a small desktop
Newegg.com is a good place to find all the components you need to complete the final assembly of a current barebones Shuttle system. My Shuttle, a model SN68GS has been chugging along on Ubuntu beginning with version 7.10 through 9.10. I have never had any problems with it since I assembled it three years ago. Try this link for a Shuttle that appears to meet your desired specs.
I've considered the shuttle PCs, but can't find good information about how Ubuntu-compabile they are.
All you need to do is add a CPU, memory, hard drive, and CD/DVD reader. Once you gather all of your peripherals, you can complete final assembly in a couple of hours followed by installing Ubuntu in less than an hour. It should work great.
Software expands to consume available system resources.
Be cautious, be vigilant, and beware of omnipresent Big Brother.