competitive SnD rulesets livestreaming, ESL - CB etc
This is about the best that can be done without mod tools atm (although u may dissagree on the specific limited weapons etc).
Kaostv are livestreaming MW3 ESL SnD league here, there are 256 teams signed up:http://www.twitch.tv/kaostv3
more info here:http://www.esl.eu/eu/mw3/forum/#/eu/mw3/
There is a clanbase league also:http://clanbase.ggl.com/news_league.php?lid=12491