I’m a huge fan of the Mac mini as a server, and while there are some nice options for sticking the things in a server rack, the xMac mini Server by Sonnet is the most capable one I’ve seen.

The $1300 1U enclosure has a built-in power supply and fan because it’s far more than a rack — it’s a complete system. It pack one PCIe 2.0 x16 (x4 mode) slot and one PCIe 2.0 x8 (x4 mode) slot via Thunderbolt for expansion cards, letting the Mac mini use fibre channels, high-powered video cards and more.