What experiences do you have with Stackless Python and PyQt?
Issues i would be happy if people address:

Compilation of PyQt for Stackless: does PyQt need to be compiled especially for Stackless? is the compilation smooth? problems with bindings etc.
Stability: any unexpected crashes, freezes, pauses and other weirdities?
Memory Management: any hints of memory leaks. comparison of RAM needed for a Stackless/Plain Vanilla PyQt applications
Software Engineering Empowerment: very short outline of flow-of-control models for Stackless-powered PyQt applications
Lessons learned: any painful lesson learned, traps to be avoided, problems to tackle you might have experienced

Be Happy
I tried to go down this path several months ago and decided it was not worth the effort.
I was able to run a binary install of PyQt (on Windows) against a stackless version of Python, but I found that I had to manually go in and change some of the files.  I was getting an error message (sorry, I forget what it was), and google search led to a solution from several years ago.  Newer code did not include the old fix, so the change was not too difficult and (if I remember correctly) it was in python, so no recompile was necessary.
But that was a deal breaker for me. Qt updates come out regularly, as do updates to PyQt, and I didn't want to be continually fixing the code.  Stackless and PyQt are simply not used enough together to be checked out thoroughly.  I found the risk of difficult to debug issues pretty high. This is especially true given the author of stackless has moved on to PyPy.  Let me apologize in advance - I wish I had the references I found for the author stopping development on stackless python and more detail on the errors I had to fix - I wasn't expecting to regurgitate the details on Stack Overflow.
So I chose to run PyQt on a vanilla Python instead of stackless.
BTW, I also thought that mixing signals/slots with stackless code would be confusing, as they are completely different methods of solving multi-threading problems.
Good luck!
Stackless Python and PyQt