if you want 30 teams or somethign like that, you may need to edit the xml files a bit.
copy/paste the cultural bonus of india to the american section - you can have multiple bonuses, but there is a cap at some point. i tried adding all the useful ones once, lol.
anyway, once pasted, re-read their description and edit them so that you don't get unhappiness from population nor from number of cities. one of them must be reversed from their current state.
30+ cities is no problem now.
another cool lil hack is changing the manifest destiny % deduction for buying tiles. set it high enough and you end up getting paid to "buy" tiles.
you can do some creative stuff in the xml files. make units. even add graphics of your own creation. maybe a settler that can move 20 spaces or a worker that works 1000% speed
or even handicap yourself.