May I ask why is GtkD not an option? Do not get me wrong, I am
not a GTK advocate, I am myself a FLTK user/developer. However,
GTK would probably be my second choice after FLTK, if I ever
had to chose another GUI toolkit for my
C++ projects.
Look at this comparison: http://bit.ly/KFbLbs
In short, QT has much more to offer and was built with OOP in
mind. Its more portable. QtQuick. MVC, MVVM patterns.
But unfortunatelly much harder to use with D :(
Even Ubuntu's Unity is being rewriten to Qt (from GTK).
I think that something like SIP (for python) is needed to make
the bindings possible and maintainable. Don't know if swig will
be enough alone?