I am using one of the in putting together a Low Tech Lagering System (presented in the Basic Brewing Video on Lagering). It is the 60 Quart Igloo Ice Cube. Mine will work with a temperature control unit that will circulate cold water for cooling. You coul also use water, and some frozen water bottles to control temps. But short answer is Yes you can use this to control fermentation temps.
Bought two this week...already used one for cold crashing, going to crash two more batches and temp. control a brew tomorrow. Fantastic dimensions on these things!
I use one as a swamp cooler in my basement and add an aquarium heater when neccessary. I made a foam top for it bit it's not really neccessary. I'm actaully going to use it as a BIAB hybrid mash tun on brewdays too.