>Can you create a VFP dll (that contains VFP commands that VB does not have) that VB can use like you can create a VB dll that VFP can use?

Yes; a VFP in-process server (.DLL) can be instanced in VB, and VB .DLLs are COM objects, too, so you can CREATEOBJ() them from VFP. You need the runtimes, and in the case of a VFP .DLL, may not use any UI elements in the in-process server.