They would seriously have to be cleaned given how toxic the paint on those things is. Plus, I would rather have something not prone to giving the local inspector a fit.

I have no experience with them myself, but I know there's a good bit of interest in them for non-traditional uses. A Google search for shipping container homes will turn up a lot of interesting results. It still might give your inspector a fit, but there are resources out there. You wouldn't be blazing completely new ground.

I don't see a lot on insulating and we are a bit far from the coasts to make availability great. There was a thread a while back where these were discussed.