Apple iMac 27-Inch Intel Core i7 4 GHz Retina 5K Late 2014 32GB RAM 1TB Fusion | eBay
A-Tech 32GB Kit (4x8GB) RAM for Apple iMac (Late 2012, Late 2013, Late 2014, Mid 2015) | DDR3 1600MHz SODIMM PC3-12800 204-Pin SO-DIMM Max Memory Upgrade at Amazon.com
Timetec 32GB KIT(4x8GB) Compatible for Apple DDR3L 1600MHz PC3L-12800 CL11 for iMac (Mid 2011, Late 2012, Late 2013, Late 2014 Retina 5K, Mid 2015 Retina 5K) SODIMM Memory Module MAC RAM Upgrade at Amazon.com
A-Tech 8GB RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz SODIMM PC3-12800 204-Pin SO-DIMM Memory Upgrade at Amazon.com
iMac Intel 27" EMC 2806 (Late 2014 and Mid 2015, 5K Display) Memory Maxxer RAM Upgrade Kit - iFixit Store
Apple iMac 21.5" - Mid 2014 Reviews, Pros and Cons | TechSpot
Memory in New $1099 iMac is Soldered and Not Upgradable - MacRumors