I live in one (two actually) in NH and am in the process of setting up shop in Desert Hot Springs. My site is www.leedcabins.com
The key to livability is the insulation - closed cell foam; I'm toasty in the winter (electric radiant floor heat) and ice cold in the summer (13.5K BTU RV Unit on roof). Here in the desert I now find that the a/c isn't as necessary because of the insulating properties of the foam.
Container homes and cabins can also be found here: www.leedcabins.com