I used xlw product for a number of years now and it is a great framework. Recently I had to do an add-on that required the usage of Qt. It turned out that, after compiling XLL addon with linked QtCore and instantiation of QCoreApplication, the xll cannot be loaded into excel. Excel complains about the xll having an incompatible format...
I think that being able to use Qt in addition to the Code::blocks will be a great addition to XLW product.
If there is an interest I can put together a test project that demonstrate the problem.