The most recent iMac 21.5-inch teardown at iFixIt revealed an interesting tidbit: unused mounting points that were curiously in the shape of a 2.5-inch hard drive.

After a bit of investigating, iFixIt found that all mid-2011 21.5-inch and 27-inch iMacs can accept an additional hard drive, regardless of whether or not Apple will let you outfit your machine with a second drive.

“However, all was not peaches and roses,” says iFixIt. “We also found that although some iMacs may have mounting holes for hard drive brackets, others don’t. Which is unacceptable. Users should be able to upgrade their iMacs to dual drives if the functionality is there.”

So iFixit has introduced the 21.5-inch iMac ( and 27-inch iMac ( ) Dual Hard Drive Kits for US$69.95. These self-install kits work on all Mid 2011 21.5-inch and 27-inch iMacs. With the kit, you’ll be able to install OS X on an SSD for fast startup times, while still being able to use your original hard drive for mass storag

You can check out the 21.5-inch iMac and 27-inch iMac dual hard drive installation manuals to get a feel for the install process at and .