Thanks for the input. I had assumed that going below the suggested ferm temp would stunt the yeast growth. I'll try going cooler for my next brew and see how that goes.
It can. It's definitely depends on the strain. Keith (majorvices) recently posted about US-05 fermenting in the 40's. Unless you want to experiment, I would stay within a few degrees of the low end to be safe.
I've run 05 in the mid 50s and 1007 in the high 40s. Of course, experience pays when it comes to yeast abuse, but in general I feel that the recommendations you get from manufacturers are too high.