The middle board is essentially plain old Monopoly.
The inner board is Super Add-On Monopoly revised in the standard Monopoly style. The only changes are the elevators are now called "Transit Stations" And Travel cards should be shuffled in with the Bus Tickets from Mega (because they do something similar). I changed San Francisco's Market Street to The Embarcadero since the Outer Board has a Market Street in the Philadelphia properties and I feel Market Street is a more major Street in Philadelphia than SF. I also revised the colors to not overlap any others, so we have, starting in the upper right hand corner, Miami (Brown), San Francisco (White), Boston (Black), New York City (Grey).
I think I ran out of colors!
I really do not have rules written for this yet. It was just a fun art project for me, really. Also, this is FAN ART. No copyright infringement intended. Monopoly is made by Hasbro. Super Add-On is made by RAD Games and Monopoly: Mega Edition is made by Winning Moves (licensed by Hasbro). You should go out and buy all 3! I did!
EDIT 10/3/16: By popular demand, there is now a high res version of the board here: https://jonizaak.deviantart.com/art/Ultimate-Monopoly-Board-Super-High-Resolution-638080205
EDIT 11/20/18: Fixed price typo on Decatur St. Also, here is a hi-res board with the inner track (Classic Monopoly) squares restored to their original spots here. https://www.deviantart.com/jonizaak/art/Ultimate-Monopoly-Classic-773473205
EDIT 11/21/18: Link to a PDF printable board made by CoolGamer3187 here: https://www.deviantart.com/coolgamer3187/art/Ultimate-Monopoly-Board-Printable-760328927 Thanks for making this. It's something I've been meaning to do for a very long time. Also check out their Ultimate Monopoly Cheaters Edition: https://www.deviantart.com/coolgamer3187/art/Ultimate-Monopoly-Cheaters-Edition-760121902
EDIT 3/3/19: A minor fix.
Just a question: the transit stations are bi-directional (i.e. they work from inside to outside and vice versa) or only from inner to outer rings? And station rents must be paid if a player stops on the station only or even if he/she stops on the transit? Thanks