As discussed on IRC (#pyside @ freenode):

Replacing all "model" occurrences with "self.model" and all "pickselector" references with "self.pickselector" should avoid the segfault.

It happens because these two objects are being destroyed by the Python's GC once they leave the constructor scope. It still needs to be checked whether this needs fixing on PySide or not, but the changes above should work just fine.