I have a buddy who has looked seriously at it...it definitely has its pros and cons. It's a cool idea and in theory it can be cheap, but once you get it outfitted for human living (insulation, doors, etc.), add in services (ex. if you want off-grid - well water, septic, solar, 4G MiFi, etc.), and buy/lease land...well, it adds up.
A lot of times it makes more sense to simply buy an RV, even a used one...it has built-in hookups for water, power, sewer, etc., an engine so it's easy to relocate, a bedroom & bathroom, etc. Another alternative is a "fifth wheel", which is a towable, non-engine version of an RV...usually quite a bit cheaper (due to not being a truck) and more spacious:
http://www.forestriverinc.com/ConventionalFifthWheels/
You can get RV towing services when you need to relocate, so you don't have to keep a truck around to pull it where you want, and there are plenty of camping grounds and snowbird spots where you can stay for pretty reasonable rates. Then you're not stuck in one place like you would be with a shipping container, paying taxes on the land, etc.
If I had my way, I'd just live in an extended stay hotel...freedom to relocate, only a little more than the cost of an apartment, maid service, etc. :awe: