Many thanks for your reply, stress_junkie
There was no "Use KDE settings for Gnome applications" in my kcontrol, even after I installed gtk-qt-engine, so I ended up installing the QtCurve theme, and setting it as the default style/theme in kcontrol and gnome-control-center (as explained here: http://susewiki.org/index.php?title=..._using_QtCurve
). The solution to the non-persistent settings was also described in there. It was simply a matter of adding the gnome-settings-daemon to the kde autostart folder.
The screensaver and mouse acceleration are obviously still being messed up by the gnome settings, but I can live with that for now.