I thought about this for some time now and looked in Bnet about leagues. Then I saw that you could create a custom league, but requires alot of work. So I guess my question is: How do you create a custom Starcraft league?

Answer: It's a lot of work... you need a bunch of stuff and have to talk to blizzard---just run your custom league on your own or off battle.net. I think WGTour might be the only one setup officially through battle.net right now...though I could be wrong.

I run a UMS Ladder off b.net without being a registered league .

http://z14.invisionfree.com/Civ_World_League/