that is the sort of heater I am looking for so I think it is not such a big deal to find a suitable supply. Here is one for $60:
http://www.mpja.com/productview.asp?product=12614+PS
Would be a lot nicer if they were AC though...
Don't forget you will need to be able to monitor current and voltage with a pretty high res... This I guess gets expensive fast (but you suspected that right?)