I use a plastic fermenter and a swamp cooler. I also use big blocks of ice, like bricks, to keep the swamp water in the low sixties. I haven't had a problem with stuck or dormant fermentation, except the dreaded 1.020 fg extract problem a few times, which I was getting before I started using a swamp cooler.
Just brewed a pale ale, went from 1.045 to 1.010 in a week, so I guess it worked. No clue what the internal temp was though...