O Rich, that is a far better idea than I thought you meant it to be.
But, it does go back to getting a floor plan lay out and players knowing where they are setting up prior to the event. Even still having every body being able to quickly move around, as quickly as a gamer with a movement tray filled with models can move anyway.
Some players are going to field alot of models not matter the game. Its the player fielding what he wants, if we can avoid some of the choas of set up it would be ideal. No one wants to be the kid losing it because he feels clostrophobic from 20 people coming in from all sides. Also, no one wants to play next to a guy after he screamed at you for setting up too close to him.
If we could organize a floor layout and have the respective sides get their tables set this movement tray it idea "could" work.