Can I build a base control class and use C++ inheritance to derive other controls?
Yes, it can be done and is fairly easy. The tricky part involves setting up the MFC-based macros that are used by AppWizard and ClassWizard. When deriving from the base class you have to cut-and-paste to build the ODL file properly, use specific base-class DISPIDs, etc. All of this is explained in detail in Microsoft Knowledgebase article Q138411. An example is also provided (SHAPES2.EXE) that illustrates the techniques.