It’s a long shot, but Donny and Marie Osmond could make a comeback as hosts of their own daytime talk-variety show. Agents are pitching such a project, but sources said a deal might be difficult, in part because the Osmonds currently have irons in other fires, including work on Broadway. Studio sources said William Morris is packaging the show, but there’s no word on whether any syndicator will be willing to step up and make a bid. The original “Donny and Marie” aired on ABC primetime in the mid- to late ’70s. William Morris declined to comment.