By Mike Dolan LONDON, Feb 15 (Reuters) - The jury's out on the big investment theme of 2013 - the so-called "Great Rotation" out of expensive bonds back into undervalued equity - and don't hold your breath for a verdict any time soon. Only six weeks into a new year is early to judge what many see as a glacial shift that could take more than 10 years to play out, reversing a move into bonds by major pension and insurance funds that itself took a couple of decades. But with market pr