GIMP UI Redesign Project <http://gui.gimp.org/index.php/GIMP_UI_Redesign>
It looks a quit interesting issues happens in open source domain. AFAIK,
some other project like blender or some uml modeling tools experience the
same kind of issues.
The things here interesting is;
1. there's a concrete project with concrete domain, also user there
2. it tries to adapt the open source model, try to march to open