The grand plans of Rich Coleman, CEO of GenStone Financial, to head the largest minority-owned mortgage firm by purchasing Ann Arbor-based Washtenaw Mortgage Co. have gone bust (see IMP, 11/18/2005). Final details of the sale hit impassable road blocks and the companies elected to call off the deal. Washtenaw made the announcement Dec. 6 in an 8K filing with the Securities and Exchange Commission. …