I'm all in favor of devices that fill more than one need, but I'm really skeptical that this could do much besides act as a hand warmer. A cast iron pot on a regular propane stove might heat up your van just as much, at a fraction of the cost. The camping manufacturer Century makes a stove/heater combo that puts out twice as much heat for under $50:
You'd have to have adequate ventilation, obviously. I use a Mr. Heater and a small Coleman stove; they take up a little more room than that alcohol stove but are much more powerful; and the Mr. Heater can just warm up the SMB. Anything smaller would probably not work very well.
BTW, don't seem to be any catalytic heater/stove combos. Never tried to heat something on mine, but kinda curious why there aren't at least catalytic stoves, since no CO.