I noticed that in the new PR1.1 firmware there seems to be height limit for the QPushButton in Qt. After some quick testing, I came to a conclusion that the height limit is 72 pixels. If it's more than that, the graphics will go wrong by painting a duplicate button of the remaining pixels.

But they do look much cooler now. Also the proper Maemo menu works now. I just have to figure out a way how to display the menu items without the leading menu name on them...