PyQt4 4.6 has been released. Also, the latest version of PyQt4 in Portage, 4.5.4-r4, is blocking Qt 4.5.2. Reproducible: Always
So maybe the blocking thing is something weird going on with my laptop, because it didn't happen on my desktop. But in any case it would be nice to have PyQt4-4.6 in portage.
The blocking behavior that I was seeing seems to be a result of the fact that qt-gui-4.5.1 has the dbus USE flag enabled by default while qt-gui-4.5.2 does not. So it's not really a problem with the PyQt4 ebuild; it was just a result of less-than-ideal dependency resolution behavior by Portage.
PyQt4-4.6 makes pykde to break. https://bugs.kde.org/show_bug.cgi?id=209164 So for now, PyQt4-4.6 will stay on qting-edge overlay until all the regressions are fixed