Yes, Shrieker only as primary weapon, USP as secondary, flash grenades so that no grenade damage can occur, either explosive focus or energy focus, ammo belt, supercharger and improved energy or explosive damage.
There have been other tournaments in the past. There was a very successful USP shoot out.
NNID - AndyInTheUK Mainly playing Zombi U. Currently Number 2 on the Standard mode Leaderboard for Zombi U. http://i.imgur.com/YD02k.jpg