InstallAware

A quick thought comes to mind: compiler variables might do it for you. You can add these into a project before you build the media and reference them in your MSIcode to copy specific files or run other actions.

As Bokkie says, compiler variables are a good option. Another interesting option would be to not actually do any compile time customization but do it all at runtime! This is where you'll really get to feel the power and flexibility of InstallAware. For instance, an INI file could be read for any/all kind of parameters using Get INI Settings