I’ve been struggling with exactly the same problem myself.
I tend to think that the bbPress profile is the correct place to store and edit this information. Here’s what I see as the requirements:
1) Plugin for WordPress to redirect the “Profile Edit” link to the bbPress profile edit screen, as well as link the profile view to the bbPress profile view.
2) Plugin for bbPress to allow for editing of WordPress profile fields as well as a customizable list of new/extra fields. I believe that there is a plugin that does at least part of this already.
3) The bbPress plugin would need to either know about WordPress settings like notifications, or would need to run the wordpress plugin filters that apply to profile edit. I’m not sure that the latter would be easy.
That’s a great idea for a plugin. Seems like a logical extension to the posts count plugin.