Well, reading in planetkde about how nice data aware widgets would be, I have to say this:
Data aware widgets are great
Data aware widgets in C++ are not the best possible solution
Using a higher level language, and specifically a more dynamic language makes lots of things much simpler.
As a tiny, lame example, please check the little thing I wrote about data aware widgets in python here.
I am sure that some of our better programmers (or more creative thinkers) can come up with awesome stuff if they divorce from C++ in this subject :-)