I would like to inform the community about a little library project that started out as a university research related project and matured into an open source project. It is basically a library of widgets for scientific/engineering applications with focus on excellent Qt designer integration and the goal to be "most easy to use" (targeting students who are just beginning with C++ programming and Qt). The library is not very large, but the widgets are stable and work IMHO nicely.
Let me know what you think, here's the link:
http://qnanwidgets.sourceforge.net