Okay, can you somehow hook this stove up...
Okay, can you somehow hook this stove up to a 20 lb propane tank? And what would that entail? (We do both car camping and third world travel...don't want to have to buy 2 stoves)
Not really. There would have to be some sort of pressure regulator which would step down the pressure from the tank to the stove but I don't believe we have any sort of coupler that would do that. Certainly not recommended by Primus.
That is a really awful idea unless you were hoping for some type of mythbuster like explosion. Camp stoves should only be used with fuels they are designed to operate on safely.