iFixit took the results of its Mac mini teardown to heart on Friday and put out an upgrade kit for buyers. Its Mac mini Dual Hard Drive Kit lets those who bought the 2011 Mac mini add in a second drive if they didn't either build-to-order the solid-state drive or opt for the server version. The kit includes a needed special SATA cable as well as the mounting equipment, a 26-piece bit driver, a spudger, and iFixit's own mainboard removal tool.
The upgrades should work with any 2.5-inch SATA drive, including SSDs. Both the boot drive and the second drive are replaceable, although the boot drive will demand having an external Lion Recovery drive to get the OS back.
Adding in a second drive requires disassembling much of the system and could break the system or void the warranty. Potential upgraders should be comfortable with their abilities and the consequences before they add a second disk. The kit is available now for $70 and has a six-month warranty for its own parts, but not the Mac mini.