Exactly this.
I didn't try this, and I suppose that some low level pointer rewriting would be necessary to do this.
I'm not sure if it's expensive though, maybe you can replace the pointers without resolving the stacktrace.
The problem is that to get the stacktrace of the task creation you have to traverse the stack at that point in time. You can't really do it later. And stack traversal using DWARF unwind info, for example, is neither cheap nor simple. You might have better luck if you compile with frame pointer though.
