I ended up buying a SS coil and bulkhead qc fittings for an internal chiller. Basically a wort chiller with ice water / glycol. I will wrap the outside in heat tape of the equiv just like my carboys. Then use the same two stage controller to run the pond pump / heat. Not a jacket like the carboys I know. But I really do expect this to be a more efficient means of cooling.
Now if I only had time to put the pile of parts together...
Bottom of this link has images of where I stole the idea from...
http://discussions.probrewer.com/showthread.php?22617-temp-controlled-plastic-conical/page3
I have done almost the same. I have SS coils mounted to the lids that I pump glycol through accompanied by a pump and valves controlled by a BCS. My SWMBO has/is sewing jackets for them. Basically using multiple layers of the same material that a heavy quilt is made from. It seems to be able to drop temps and maintain all 4 of the fermenters decently.
FF recently released their jacket but it does not contact the fermenter fully. Merely maintains ambient temp around the fermenter.
http://fastferment.myshopify.com/