I think the only way to get custom titles on a phpbb forum is for the admins to enter them individually as the users request them. There's a little too much traffic and too many members here to make that really feasible.
Custom modules exist for phpBB that allow this feature, for example:
I've never used that particular module so I don't know how well it works, but according to the documentation it is configurable to allow users to edit their own custom titles.
Why don't you set up your own site Jason, and set it up to how you like and to your standards?
I think that is an EXCELLENT idea, and just what I was thinking! It could be a site for people who want cake business advice from someone who does not make cakes. I wonder how many people will sign up? There's got to be a huge underserved population of those kind of people out there. I think we've found your niche for you, Jason.