MSI is a company known mostly for its PC components. They recently jumped into the netbook bandwagon with just about every other major pc manufacturer. Their Eee like machine, the MSI Wind, ended up being an extremely popular little laptop. Along with the laptop they made a not too well known desktop with roughly the same dimensions as a ream of printer paper.
The MSI Wind PC is a great computer; I have three of them. It comes with a 1.6GHz Intel atom CPU, two SATA connections for 3.5″ and 5.25″ bays and 6 USB ports. You can pick a barebones one, requiring ram, a hard drive and possibly DVD drive, for $140 or so..
How to roll your own Mac for under $240