Pro/E is not used for Architectural Design unless it is used for Architectural Design. Our company has been using Pro/E for Architectural Casework and Millwork for 4 years now very successfully. Unfortunately, we can not give out our models...I just wanted to add my 2 cents. PS: It is also used in the jewelry industry as well which is not a mechanical application.
Pro/E can be used for whatever you want - it doesn't know the difference. It just depends on what level of functionality you need out of it. As a Mechanical Engineer, it's perfect for designing medical implants. As a homeowner, it's sufficient for designing garages, closets, decks, etc. I probably wouldn't use it if I were an Architect doing building design everyday.