Mayor Bloomberg has banned smoking in bars and trans fat from restaurants, and now he’s pushing to curb another appetite: donations to local pols from those who conduct business with the city. Since the fall, Bloomberg staffers have been meeting with City Council Speaker Christine Quinn and her minions to draft language for such a bill. “It’s a big undertaking,” says Michael Casertano, spokesman for Councilman Simcha Felder, who would introduce the legislation as head of the government-operations committee. During meetings, Casertano says, Bloomberg’s crew has argued for a total ban, while the council factions (non-billionaires who rely on campaign contributions) want something less drastic, such as decreasing the maximum $4,950 contribution to a nominal amount. Of the $40 million given to pols in 2005, the estimated amount of “doing business” money was $8.6 million. If passed, the ban would be one of the toughest in the country; it could also create a fund-raising scramble for wannabe mayoral candidates (like Quinn) who need to raise cash for 2009.