i'm sure walter will get back to you, but if you are looking for an internal solution, i'd just buy an internal ssd... unless you had a plan for the external enclosure.
i believe the 2011 imac has a sata3 internal bus, so you should be able to use a 6gb/s ssd. owc has several to choose from, a 120gb runs under $200:
http://eshop.macsales.com/shop/SSD/OWC/Mercury_6G/
double check with them about specs for your imac model.
also, i think bang for the buck, i'd get just one ssd and use that as the boot/application drive and keep the standard hd for footage.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW
