I had some experience trying to get one of the software that used PyQt. first you had to have a particular version of Qt. Then a particular version of PyQt. If the version of PyQt did not like the version of the installed Qt libraries, you had a problem.
I tried several combinations and at the end could never get the program to run. Anyways, if I had spent only about ten thousand more hours on it, maybe I could get it to run.
So again, if you use Qt only and make it statically linked, chances are that you won't get into trouble with layers and layers over one another.
Any binary compatible version should work, and Trolltech are good at making their major releases binary compatible. Your PyQt problem is more likely to be the well known SuSE issue than anything to do with Qt. Mind you, I agree with your underlying point: PyQt is excellent; PerlQt, er, isn't. :o) -- "...our desktop is falling behind stability-wise and feature wise to KDE ...when I went to Mexico in December to the facility where we launched gnome, they had all switched to KDE3." - Miguel de Icaza, March 2003