As for collection quests I think I might have a way to make it work for instances, but I'm still a week or two away from getting my 5 box setup completed and working to try it.

My thinking is since if you do multiple instance runs to level that collection quests in there would work given you do one char with the quest at a time. With FFA loot and synced wireless mice it'd be pretty simple to just loot twice, as only the char on the quest would get to loot the second time.

This might only work with multiple box setups only. For those who use software to have multiple open windows (like WoW Maximizer), even if the mouse isn't syced per client it still might be feasible to just slide mouse to correct char, loot, hit hotkey to reform follow formation without really slowing progress.

Though it's really only beneficial if the quest is shareable, just share it before the last item is gained on the char with the quest active. Then turn in the quests all at once.

Doing it this way may just provide a reasonable XP boost, as opposed to trying to do 5 chars on the quest at the same time out in the world killing non-elites where the XP gain is definitely hindered.