This is a modification to preferencesdialogbase.ui to make the dialog have a smaller minimum size. I didn't change any strings, but Qt designer did decide to add a few keyboard mnemonics to the ui file. If I hadn't refrained from changing strings, I probably would have replaced certain labels, like "Colorkey:", with groupboxes (I didn't want to remove the colon from the end and then have to update all the translations). If you accept this but then still want to make the dialog smaller, the interface page is the biggest one after applying the patch, so you would need to start there.
If it matters, I made the patch using the qt3-designer v3:3.3.7-4 package from Debian.