Eleven years ago, if you wanted to live downtown there was really just one choice: the pink Railyard apartments near the convention center. In fact, the Railyard is so close to the convention center that half of the units needed to be knocked down to build the convention center extension. The remaining units are no longer pink, and they are no longer rentals. But there are now more choices than ever after an amazing decade-long expansion of the downtown rental market.Last year alone, more than 1,200 new downtown rental units emerged. Unbelievably, more than 900 of these . . .