Thank you both, i'll check tomorrow at work and provide updates.
Oh, and Sv0lli, thanks for the PSQL plugin!
Another thing, now it's getting weird.
I made a fresh install of Core in Virtualbox at home. The same settings, the same extensions. And PyQt works...
So, since a VBox is i686, and my Via Epia on which I'm installing the problematic Core is i486, then one of the extensions is broken. I asked PyQt/sip maintainer about the compilation options, yet to hear an answer.
Meanwhile:
GDB shows that SIGILL is thrown from sip.so, so we have a suspect.