Lindows.com is already creating boxes like this
http://www.ecommercetimes.com/perl/story/20591.html.
However, I like my machine running RH9 and mythTV. Several guys at the
local Internet Cafe have created myth boxes relatively cheaply. I've been,
myself, trying to get the owner of the cafe to sell these machines prebuilt.
We built one for the owner with a 120gb hard drive, 512mb DDR ram, a
WinFast 2000 tuner, and a GeForce2, and CD burner, all in a shuttle case
for about $650, in parts. That of course is with no markup. However, the
XP Media center machines are running at more than double that.