Kayali looks very interesting! And I'd love to be able to work on and
improve a Maxima GUI built in Python (though Lisp would be better...).
Unless I'm mistaken, though, Qt and PyQt are only available for
Windows under a commercial license (with some sort of exception for
academic use). Maxima has always been fully free (in both senses) on
all platforms, and I think it's important to preserve that.
-s