According to this story, former Massachusetts Governor William Weld may seek the Libertarian Party vice-presidential nomination, if the party nominates Gary Johnson for President. He was the Republican Governor of Massachusetts 1990-1998.
Weld has a history with the Libertarian Party. In 2006 he was a candidate for Governor of New York. He accepted the Libertarian Party nomination for that office, but he was also seeking the Republican nomination. When he failed to get the Republican nomination for Governor, he then withdrew entirely from the race, and the Libertarian Party had to find a new nominee.