Jon,
I have seen some instances of missplaced buttons in the last 2 (I think) betas.
See the attached image of buttons trying to locate the Outlook 2010 splash screen.
Related to this discussion of buttons , I seem to remember that UltraMon buttons didn't load or loaded different buttons on dialogs\splash screens. This seems a sensible approach, however, you have a far greater level of customization, which may make it more difficult to program. Having an option to disable buttons on certain window types may ne useful?
Just some thoughts...
Pete