I believe Scheme basically only uses the heap (which is necessary because of call/cc iirc).

Haskell uses a variation of a G machine (looks like a spineless tagless g machine to be specific). The way that works is that they convert your program into a giant lambda term and then they work on reducing it. This of course looks nothing like a traditional call stack, so you can replace that whole thing with the G machine. Recursion (at least of the non-tail recursive variety) will look like a lambda term slowly getting bigger in heap space.

And then I also heard of someone (I forget which language) talking about setting up some logic to look for stack overflows and then throw all the current stack onto a heap and then start over.