Special needs require special programs. I was needing a special listbox, with variable number of lines per row. Even I have found some listboxes that accepted more than two lines per row, they didn´t allow to mix rows with different number of lines.
So, I decided to create my own listbox, drawing it on canvas and using PyS60. If you are interested, see the video and download the demo source code or sis. It may be a good starting point for other listboxes, for instance. The code was tested only in Nokia E71 and Python 1.4.5. It is not prepared yet for screen rotation.