I actually think the magic number for Don’s 20 year plan is 30, just like the NHL and the NBA. If you look at the map above there are 29 markets indicated on the map, those were cities that 4 years MLS was already looking at, it would be easy to add one more market (Orlando, San Antonio/Austin, Carolina, Phoenix, or ??) to that map. Then you get the two conferences of 15 teams each with 3 divisions of 5 teams each.