That shows a big difference between New York and Illinois. There are pockets of GOP voters in NYC, in places like like Staten Island. I can't imagine any of Romney's "best districts" in Illinois were within Chicago city limits. In fact, I'd be surprised if he won a single Chicago ward or senate district. Bush won only 1 ward out of 50 (Ward 41), and that was the "traditional GOP ward" with a Republican alderman and state senator, and he only won it by like 52% or something (I think the GOP state senator got 63% in that ward, so Bush ran behind)
And when it comes to the city vote by religious breakdown, I was arguing with an anti-Catholic freeper who said the protestant vote in Chicago is probably more GOP friendly than the Catholic vote and makes up the bulk of Republican voters in the city. I'd say its the other way around, since most of the protestant majority areas of the city would probably be black neighborhoods (heavily Baptist) and they gave Obama more than 95%+ of the vote. Romney did much better in white Irish Catholic neighborhoods like Mt. Greenwood (ward 23, Romney got 30% of the vote) You can see the totals here:
http://www.chicagoelections.com/wdlevel3.asp?elec_code=19
As for the Jewish vote in Chicago, I don't think there are many Orthodox Jews within Chicago city limits. I'm guessing the "overall" Jewish vote in Chicago went overwhelmingly RAT, but that differs little from the city as a whole.
I remember Perica carried 12 wards when he ran against Stroger. He did well enough in the city to win, but not well enough in suburban cook.