Daily Item Staff ReportBOSTON – Gov. Deval Patrick is set to file legislation today which may set off a billion-dollar bidding war for the rights to even build a casino on the North Shore.The governor’s bill, according to the Associated Press, also carves out three geographic areas that would each get one license, and that could pit North Shore race track owners at Suffolk Downs, which straddles the Boston-Revere line and Wonderland in Revere against the cash-rich Las Vegas Sands Corp.Suffolk Downs is owned by Richard Fields, a former associate of Atlantic City casino developer Donald Trump. Fields partnered with the Seminole Tribe of Florida to build casinos there and bought Suffolk Downs this spring.The billionaire chairman of Las Vegas Sands, Sheldon Adelson, is eyeing a Marlborough site for a casino. Under Patrick’s plan, both Boston and Marlborough are in the same region and would get only one license between them.As drawn, Patrick’s map raises barriers for any North Shore-area developer because they would have to outbid Adelson, chairman of the world’s largest casino company by market value.Region 1 on Patrick’s map includes Suffolk, Essex and Middlesex counties. Marlborough is on the western edge of Middlesex County. Suffolk Downs racetrack and Wonderland Greyhound Park are in Suffolk County. Operators of both tracks have signaled they’ll bid for a casino license.The bill would require bidders to own land and put up a minimum investment of $1 billion, ensuring the proposals would be resort-style casinos. License auctions would be staggered, likely over a period of nine months.Patrick, in earlier outlines of his plan, estimated three casinos would generate $450 million in annual tax revenue and 20,000 jobs.The filing of Patrick’s bill is expected to kick into high gear the lobbying on both sides.House Speaker Salvatore DiMasi has said he’s skeptical of any plan to bring the “casino culture” to Massachusetts.The governor’s plan would also give preference to bidders who partner with an Indian tribe, and would require approval from the communities where the resort-style casinos would be built.The legislation favors the newly recognized Mashpee Wampanoag tribe, which won community support this summer for building a casino in Middleborough, where it already has purchased several hundred acres of land. The tribe also has well-financed support from the former developers of Mohegan Sun in Connecticut.Middleborough would be in a separate region. A third region would include Palmer, where another casino has been proposed.Patrick, when he announced Sept. 17 his intention to file casino legislation, said at least one of the licenses would have “a Native American component,” and said he would give special weight to the newly recognized Mashpee Wampanoag tribe.The Aquinnah Wampanoag Indians also have declared that they would open a casino if the Mashpees do the same.Daniel O’Connell, state secretary of housing and economic development, told Taunton area business leaders on Wednesday the governor’s plan also would include a protection and mitigation fund for neighbors.”It’s very important for a host community to weigh the pluses and minuses and decide if they want this,” he said, according to SouthCoastToday.com.The Mashpee Wampanoag tribe’s proposal for a $1 billion resort casino in Middleborough sits in Patrick’s “region 2,” comprised of Norfolk, Bristol, Plymouth, and Barnstable counties, along with the islands.The tribe’s partners include Sol Kerzer and Len Wolman, the developers of Mohegan Sun Casino in Uncasville, Conn. They’ve proposed a 850,000-square-foot complex that would include a 10,000-seat auditorium, a 1,500-room hotel, 4,000 slot machines, and a golf course.Under Patrick’s plan, the state’s two other racetracks – Plainridge Racecourse, a 91-acre harness racing facility in Plainville, and Raynham Park – would have to outbid the tribe, as would any proposal from New Bedford.The third region includes just about all of cen