2013 iMac teardowns reveal SSD slots, soldered-in CPU in the 21.5” model | Ars Technica
maxupgrades.com: Single SSD Drives kit for iMac 27 inch 2012 Models with SATA Blade SSD Module / Heatsink/ Power Cable and DATA Cables for [SSD + HDD] with iMac Adhesive LCD Tape