I have not seen one specifically for a duece either, but I would think the cucv coolant heater is the same, albeit some differences in mounting.
I've got the cucv kit but have not installed it yet. The multifel heater in the back of the m109 is essentially the same thing without the pump and chamber for circulating and heating coolant, and that baby really puts out! I'm betting the coolant heaters will work like a champ too.
On a side note Bjorn, I was finally able to use the ether injector a couple days ago when the temps dipped below 30. Just one quick flip of the switch while cranking and the engine comes to life. A very handy accessory that should help to save on starter and battery life.