"Multiple drive connections"に関する回答This in fact' 'is'' possible. There are 3 SATA Data Connections on the motherboard. See image here. There are also 3 Distinct Power connections on the motherboard shown in the image. In order to retrofit a SSD into the new 2011 21.5" iMacs, You'll need the following parts: 539-1295 (SSD DATA) 539-1296 (SSD POWER) And the brackets, which part numbers have not been identified for yet. See image here for an idea of the fit.
"How many SATA ports on iMac Intel 21 EMC 2428 entry level?"に関する回答There are Three SATA Ports