RubberBass is almost certainly from the Yamaha DX-27. Today I've discovered a load more sounds from the DX-27, Roland Juno-106 and Korg Poly-800.
I have a similar thread going on at Remix64 and since It's mainly for musicians it seems more the right place for this topic to be.
If you want to check on progress prior to the website www.st-01.com
coming online please see: