Midstream (i.e. pipeline) giant Williams has just created a brand new executive position–Chief Operating Officer (COO). The position was created for Micheal G. Dunn, formerly president of Questar Pipeline and executive vice president of Questar Corporation. Does Questar ring a bell? It should. Questar is, or rather was, a Rockies-based integrated natural gas company operating through three principal subsidiaries. In an attempt to diversify out of the northeast, Dominion bought Questar in September for $4.4 billion (see $4.4B Dominion-Questar Merger Happens Tomorrow). Somehow Dominion let Dunn, who once worked for Warren Buffet’s Berkshire Hathaway Energy, slip through their fingers when buying Questar. Dominion’s loss is now Williams’ gain…