ORION Pictures Corp., which filed for Chapter 11 bankruptcy protection two weeks ago, said this week that it has received an unsolicited joint reorganization proposal from New Line Cinema and Metromedia Co., its largest shareholder.The plan would call for New Line and Metromedia Co., which is controlled by billionaire John Kluge, to provide an unspecified equity investment in Orion in exchange for part of the equity in the newly reorganized company. Analysts have been skeptical that debt-laden Orion, the smallest of the major Hollywood studios, could survive. The studio has not had a hit since early this year, when it released 1991's third-biggest grossing movie, "Silence of the Lambs," with more than $130 million in ticket sales. The hit followed up its success with "Dances With Wolves," which grossed much of its $184 million early this year. Orion has not released a film since "Little Man Tate," which topped just over $20 million. Its most valuable asset may be its name, distribution capability, and its 800-title library, which includes "Amadeus,Platoon,Bull Durham," and several Woody Allen movies. Details of the Metromedia-New Line plan were sketchy, but it is likely that the plan would mean that Orion would continue to produce movies at the scaled-down rate of four or five a year, with New Line taking over distribution. Orion executives say they are studying the proposal.