Sales of small apartments, also known as shoebox apartments or mickey mouse flats, skyrocketed last year. And demand continues to be robust this year. A total of 696 flats of 500 sq ft or smaller and another 1,285 of between 500 and 800 sq ft were sold last year. Buyer interest has remained strong this year with 533 units of 800 sq ft or less sold in the first four months. Such apartment sizes comprise...