Well as mentioned, the GTK toolkit would allow a lot of other ports to happen. On Linux, it seems that the interesting graphical stuff is linked against QT or GTK. Unluckily porting GTK might even be a bigger job then porting QT as at least QT was designed to be cross platform.
Wine, or rather merging in current Wine into Odin would also allow a lot of stuff to just run or be recompiled, even for GTK, it would be a shortcut to just use the Windows port, perhaps recompiled to be native.