I wrote this back in May with all of the tournament results I could find at the time (30+ players, 5+ games, USA only).
http://www.tourneyspy.com/2013/05/40k-mid-year-tournament-results-recap/
I'm in the process of updating it with new data, just about doubling the number of events included in the analysis. What I've got so far is as follows:
Army - Top 5 as Primary - Top 5 as Allies - Weighted score (primary = 1, allied = 0.5)
Necrons - 19 - 1 - 19.5
Imperial Guard - 6 - 11 - 11.5
Daemons - 9 - 0 - 9
Chaos
SM - 4 - 8 - 8
Grey Knights - 6 - 2 - 7
Tyranids - 7 - 0 - 7
Dark Eldar - 6 - 1 - 6.5
Dark Angels - 5 - 1 - 5.5
Space Wolves - 4 - 1 - 4.5
Eldar - 2 - 5 - 4.5
Space Marines - 2 - 0 - 2
Sisters of Battle - 2 - 0 - 2
Tau - 1 - 2 - 2
Orks - 0 - 3 - 1.5
Black Templars - 0 - 1 - 0.5
Events included:
2012
NOVA Open
2013 Colonial
GT
2013 Indy Open
2013 Bay Area Open
2012 DaBoyz
GT
2012 Battle for Salvation
2013 Broadside Bash
2013 Onslaught
GT/Templecon
2013 Crucible
GT
2012 BeakyCon
2013 Adepticon Championships
2012 Midwest Massacre
2013 TSHFT
2012 Feast of Blades Invitational
2013 Dark Star
GT
2013 WargamesCon
2013 Bugeater
GT