The QT-Haiku team has been hard at work and gave us a New Year's gift so to speak. According to their latest update the port reached a stage of stability which allows any QT4 designed application to be compiled and used under Haiku. They demonstrated that by adding a few more apps, in this case just some simple games and apps, all of which you can get at their download page.
The requirements for all of this to work, according to them, is a Haiku build (GCC4 or hybrid) revision 34770 or later and their new package QT 4.5.1 r110 or later. Go ahead and try it out. Well done guys.