You can build pieces of an application using AppWizard, then add them to an existing plug-in template such as npSimp32.dll. This example contains an MFC application which puts up a dialog bix as part of CCh17App::InitInstance().
To include this code in a plug-in, include CCh17Dialog (and its associated resource, IDD_DIALOG1) in the plug-in template, then call DoModal and the associated code from the plug-in. That code is currently in CCh17App::InitInstance(); you can put it in the plug-in in NPP_SetWindow() or, better still, attach it to a control.
Enjoy. If you have any questions or comments, please contact me at morganm@mail.dse.com.