I've done it before and will agree with the 10-11k limit. I've done the six 24-hour shifts a month lifestyle. It was OK. Keep in mind that you need 2-3 days to recover after each of these, so it is not as amazing as it sounds. BUT, that was also because I was doing it at a place that was seeing around 13-14k, which could be the reason I was somewhat burning out from it. That shop phased out the 24's due to the increasing volume, which is why I stopped doing it.
Question: for those of you who have done this or are doing it, how was/is your pay? My understanding is that most of these shops pay a lot less.
Final assessment: if you can find such a job that does indeed pay well (or near the same level you would get at a bigger shop), it's not the worst of gigs. It feels good to be paid $200/hour to sleep. Having said that, it's not as great as it sounds, due to the recovery days.