OWC Internal SSD DIY Kit for All Apple 27" iMac 2010 Models
Upgrade the Hard Drive in 2009 and Later iMacs
iMac SSD - 4mac
OWC SSD Upgrade Kits for 27-Inch iMac 2010
How to Upgrade iMac Hard Drive (2009, 2010, 2011): EveryMac.com
My 12 y/o son is so excited. Found him a pristine Mid-2010 27" iMac for $100. Going to give it the SSD upgrade but he's stoked to start recording music with it :
maxupgrades.com: Dual SSD Drives kit for iMac 27 inch 2012 Models with Blade SSD Module with Heatsink and Power and DATA Cables