User Management beyond WP?

I’m building a utility for stores to send information to customers and just looking for more information on something beyond the built in WP users or maybe how to use the WP users to accomplish this better. I also need it all to look like front end website and not the WP dashboard.

Not using WP in the traditional sense, so it’s kind of a funky issue. I’m getting information using an API plugin and need to distribute the info to customers for specific items.

Obviously this will be a multisite install because of shared memberships.

Here is the breakdown of user capabilities:

• 1. Superadmin – total control. Ability to add/del/mod corporations, stores, users. Send the info as a user. This is me.
• 2. Corporate – same control as superadmin, but only to stores in their group. No ability to add/delete stores/corporations, but still retains ability to modify store and user info in their corporation. Some one w/ this level can also send the info as someone else. Has ability to move between their stores easily.
• 3. Store Mgmt – Ability to mod the store info and user info for their store. Can send as someone else.
• 4. 4th Level – Can send some as someone else. Cannot mod store info. Can modify their own profile.
• 5. Salesperson – Can only send as person that is logged in and can modify their own profile.

And like I said I know pretty much all of is built into WP. I’ve never had to build anything with this level sharing of users. I’ve been considering BuddyPress for custom profile fields and the way it handles groups. I also like the notifications feature built into it which will be helpful to salespeople if someone else sends as them. Do you see BP as a good solution or is there something better out there for user control?

Thanks
-eric