Whitney tilson sent us an email about his thoughts on the latest Berkshire Hathaway buyback. Below are his notes and updated presentation on Berkshire Hathaway Inc. (NYSE:BRK.A) (NYSE:BRK.B)’s valuation. 1) Big news from Berkshire Hathaway Inc. (NYSE:BRK.A) (NYSE:BRK.B) this morning – it raised the share repurchase limit from 1.1x book to 1.2x and made a $1.2 BILLION repurchase in ONE transaction! FOR IMMEDIATE RELEASE December 12, 2012 Omaha, NE (NYSE: BRK.A; BRK.B)—Berkshire Hathaway has purchased 9,200 of its Class A shares at $131,000 per share from the estate of a long-time shareholder. The Board of Directors authorized this purchase coincident…