Check out the 2U – 4 node servers the Supermicro SuperServer 2026TT-H6RF. Nice looking upgrade from the servers I have been using and they are very cheap (like $200) on eBay as of June 2016.

This is mostly a note to self, and anyone else who builds racks based on off-lease servers.

Learned about these when I found some link to them while reading ServeTheHome.