For multi table tournaments, I generally combine the tables down to 11 instead of running one table at 5 and one table at 6. Normally, the #11 person is felted in a few hands anyway due to our blind structure at the time we usually are down to 11. Our blinds really punish the entire table quickly if left to play with 5 and 6 at two tables.
For cash, you're in a bind. I think 11 is too much for cash but I'd be okay with it for one night, or until someone leaves. In thinking more about it, I personally would rather play 11 handed still than 5 handed at a table for cash. I'm not a real fan of 6 max though like some people are.
I guess my vote overall is 11 at one table over 6/5 at two tables but I would try to avoid 11 in a cash game.
(Interesting poll results...I've definitely not in the majority here)