I use this, and mainly run KDE. You can easily install gtk themes and pick and chose which one all your gtk apps will use, or use one of the qt themes ported to gtk that come with kde. In the end, I don't think anyone can be really mad at either toolkit - it is just like how Java Swing skins everything its own way and doesn't accept any theming at all. My only gripe is that gtk2 and gtk3 apps can look radically different under the same theme, and aspects of one don't necessarily correlate to the other 1 to 1 all the time, so some themes look fine with gtk2 apps and look like ass in gtk2 or vice versa. That might be a problem with old versions of qt, but I just haven't run into any qt apps not built against 4 anymore.No, GTK is not that flexible. The only thing that can be done is to use the same theme for both GTK and Qt. For example, QtCurve or Oxygen.