Video of it being done: http://www.teamz.dk/Multi-Loot.wmv

How to:
  1. Navigate to <Path to WoW dir>\WTF\Account\<account name>\
  2. Open up "bindings-cache.wtf"
  3. Scroll down, and under the last binds, add "bind F7 TURNORACTION"(Right click) and "bind F6 CAMERAORSELECTORMOVE" (Left click)
  4. Do that for all your accounts
  5. Launch WoW and log in like you usually would do, and have all in windowed mode.
  6. Launch "KeyClone"
  7. Zoom all your characters but your mains camera into first person (just keep zooming until it can't get further in)
  8. Kill some mobs with group loot, and be sure to get so close as i do in the video to the mob.
  9. Click "F7" and watch!