I'm pitching a dark horse: Elia Tuqiri
Elia has been coaching Brisbane Fiji and Newstar 7s teams on the Aussie 'circuit' for more than 4 years or so and both teams have batted above average considering the playing personnel and the limited training time together that the teams usually have. Some of the boys in the Brisbane Fiji team don't play club rugby - only 7s.
In that time teams that he's coached have:
- beaten the Aussie 7s team (at Noosa in 2011??) then had 5 players from that side who had previously been disregarded by the Aussie 7s system, picked up in the Aussie 7s system (Newstar)
- Won the Kiama 7s, Brothers 7s and Southside 7s in 2013 (Brisbane Fiji)
- Won Byron Bay 7s in 2010 (with Brisbane Nadro) & 2011 (Newstar)
In recent times Brisbane Fiji/Nadro has produced Tevita Kuridrani, Junior Rasolea, Samu Kerevi, Joey Lala and Nemani Nadolo (and JJ Taulagi -
that's actually a 7s in-joke referring to how many teams he played for that now claim him as their own)
Newstar has produced Lindsay Crook, Pama Fou, Sean McMahon, Steph van der Walt and others.
I think he also played for Aussie 7s, and from watching the teams that he has coached it looks like he understands that 7s is not 15s but with fewer players on the field.