NEW YORK — The nonprofit Broadway revival of “1776″ will get a commercial transfer after all.After several weeks of touch-and-go negotiations, a group of commercial producers have confirmed they’ll move the Roundabout Theater Co. staging to the Gershwin Theater during the Thanksgiving weekend. Scott Ellis’ staging of the musical, which opened Aug. 14 at the 499-seat Roundabout, will be moved (at a cost of $3 million) by producers James M. Nederlander, Stewart F. Lane, Bill Haber, Robert Halmi Jr., Rodger Hess and Dodger Endemol Theatricals. Hallmark Entertainment has signed on as a sponsor. Although reviews were favorable, the size of the 25-member cast (the largest ever for a Roundabout production) apparently made commercial producers nervous. Details of the on-again, off-again plans were hammered out in recent weeks, with producers now targeting Nov. 28 for the first preview at the 1,933-seat Gershwin.