It would be very helpful to be able to specify a resource preprocessing command. It could be implemented in the specific .qrc file like:

<preprocess command="preprocessor">
<file>...</file>
...
</preprocess>

The preprocessor would get the filename of the file to preprocess and prints the processed content to the standard output to let the resource system build the .cpp file. This would be very helpful for e.g. removing comments or other stuff from JavaScript files which you need for developing but don't need for run-time. This would also allow to convert files into other formats.