The Massachusetts Supreme Judicial Court currently has a Libertarian Party lawsuit over whether the state law allows presidential stand-in candidates on petitions. The party had filed the case on August 12, 2011. The state had originally expected to respond by October 17, but it has asked for another week to respond. The case is Libertarian Association of Massachusetts v Galvin, sj 2011-0348.
The Libertarian Party is hoping that the State Supreme Judicial Court will construe the existing law to mean that stand-ins are permitted for President. The law is ambiguous, but clearly allows stand-ins for other partisan office.