I picked up a very nice Supermicro 5014C-MT server for my brother-in-law since he is in the market for a storage server. The big selling point was the four hot swappable SATA hard drive backplane in a 1U form factor. I picked it up for $80 on ebay. I added a couple of Western Digital RE3 1TB hard drives so I could create a simple RAID 1 array. The RE3 drives are designed to be put into a RAID array and have a ridiculous 1.2 million hour MTBF rating. This turn out to be something like 137 years!
Finding drive tray hardware and a suitable rack rails has been a minor nightmare. I ended up ordering the wrong rails only to find out the right rails are not listed on the Supermicro website! Supermicro tech support finally help get me straight with the proper part number.
The interesting part of the project was installing FreeNAS onto a 1 gig compact flash (CF) card which was pluged into a PCI card, a poor man's solid state dive (SSD). I found the CF card and PCI adapter card on Newegg for around $35 USD. The PCI card supports up to four CF cards. I guess you could create a small SSD raid 1+0 array if you ever wanted to.
The install went with out a hitch. I really like the CF solution since it allow you to dedicate the hard drives strictly to storage.