Trya, can you help me to understand something more clearly? Are you looking for help in ways to improve upon a given situation using methodologies OR are you looking for ways to utlilize "Black Belt" project management so that it maintains some leg room in your organization?
Sorry if this sounds like naysaying, but if you are (literally) asking for places to apply theories that will improve practices, it does not automatically sound like you are looking for solutions to existing problems for customers.
When you are looking for suggestions on where to apply Six Sigma (in the midst of solutions that already exist for particulars areas you have listed), are there reasons for looking for a place to apply it? Is it possible to take this back to square one?