Check out the thread I started called "making your own map." About halfway down the first page Tim the enchanter put a screenshot of a occ city with 3700+ sheild per turn. I'm not quite sure how he did it... I replicated his map exactly, and got up to 1500 on the first try, and 2800 the next. Still, it is better than I have ever done before!
Ref. the man below. He should have tooted his own horn, not me, but hell, I'm impressed. Him and his killer rabbit