Thanks for reading, Pat
I'm in complete control of every aspect of the build since it's all custom: Server-side code, table schema, etc. The sites would also ideally sit as sub-domains within the umbrella domain. I figure this would be best because although they are different products, they share some design templates and assets and have a similar feel.
You pretty much echoed my main concerns: maintenance and portability. There's something not "correct" in placing all the tables in one database but the idea did cross my mind. it would make it all much easier.
So, assuming I have different databases for each brand(sub-domain) how should I handle login procedure?
This is what i'm thinking:
Upon creation of an account, the user table of the corresponding site is updated with a user record allowing that person to login to that particular sub-domain.
Any potential issues with a setup like that?