IS. Meh. IS isn't going to stop your subjects moving. Period. Also I quite like the higher ISO grain noise of the 5D Mark III. IS is not an issue at this focal length
The most noise is from fanboys who don't actually shoot - they just want all the feature boxes ticked on their shiny equipment they don't use much, and not having it gives them something to complain about in forums like this. My advice - get the current Mark II, stay off the caffeine and learn how to hold the camera properly with steady hands, build a bridge and then get over it.
I've handheld my 24-105 at 24mm and 2 seconds. I routinely hand hold it at 1/5th or so. Here. This is 1/5th at 45mm and ISO 400. Would you have preferred 1/40th and ISO 3200 without IS?