Dragonchild,
I think the Win32::GUI::XMLBuilder is what you look for. Though I am not sure if you really want to use Buttons (as in Mine Sweeper for the SuDoku fields. Alternatively Tk is running fine on XP (the only one I ever had to use but I doubt there are problems with other Win32 versions.) And it keeps you platform independent.
I have been packaging my Windows applications with Activestate's PerlApp. This costs a bit but is the easiest to use. However if you try the testlicence be aware that all Windows binaries will not run after the test period has expired.
For your criteria: I have used the above all under Win32 and it worked without any trouble. For someone to come in and make a change is solely depending on your coding I guess. All this is based on the assumption you are developing on a Win32 machine.