I finally managed to get a city with more than 200 production per turn! Turns out the best way is to be the Americans, build a city next to as many mountains as possible, and then when you hit the Modern Era you build all the Wonders and buildings that bump up your production, then switch your people to only produce. Hurrah!
And then I won as the Americans too. 9 left!
you see, it is possible 🙂 !
anyway, i wish i had an xbox, the game really badly ported to the ds (only way i can play).