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
OWC 250GB Mercury Pro Legacy 3.5-Inch SSD Internal Drive Kit
Shop | StarTech.com SSD Mounting Bracket - Solid Metal - 2.5in to 3.5 Hard Drive Adapter - SSD Bracket - SSD Upgrade Kit (BRACKET25SAT) - storage bay adapter
PNY 1TB 2.5” SATA-III SSD (Solid State Drive) Upgrade Kit with Transfer Cable and Software - (SSD7CS900-1TB-RB) - Walmart.com
2.5in SSD/Hard Drive Installation Kit For Two (2) 2.5” SSD/HDD to 3.5” Drive Bay with SATA Data and Power Cables - Micro Connectors, Inc.
Rosewill RX-C200P 2.5" SSD / HDD Plastic Mounting Kit for 3.5" Drive Bay - Newegg.com