Sorry that I only answer this late (been in the hospital for a while...) To clear things up: The problem of the missing Windows x64 unwind tables is already solved! I generate them from DWARF2 unwind info in a postprocessing step.
Unwinding / stack backtraces work fine. The problem that I have is simply how to mark the try / except / finally blocks in the code with reference to each other, so I can also generate the SCOPE_TABLE data in that post processing step. Timo