Hey, dunno if it says this somewhere, but if you already have lots of money, (from owning all businesses) you can change a large empty lot into a commercial lot and in build mode place another science technology building, which you can then become a parter to or buy outright, so for every time you add another building, you add another §15000 every week to your deeds collection. This means the limit of weekly earning is no longer §68,800 but thousands MOREEE!!!!
. (moveObjects on allows you to place more than one science building(or any buyable lot) on one single lot which adds to your income)) This method isn't really cheating either, so you can have a clear conscience while you get super rich.