While I think the Tumbleweed houses are expensive, it is entirely possible to live in a small space happily. I live with my late fiance on a cruise ship in a 10x20 cabin for 6 months following Hurricane Katrina. Then we lived another 6 months in a 10x24 FEMA trailer. We found that we were quite content in our cozy quarters and saved so much money by living this way. This gave us greater freedom to do as we pleased.
After his death, I went on to buy a tiny (8x24) house and lived there happily on my own. Nowadays I live in a tiny house with my new fiance. Our small house allows us to live on a budget of a lot less than $1000 a month. We are both self employed and work when we please and love our tiny lifestyle. The freedom in our lives that it gives us is wonderful. We aren't tied down to a mortgage or scrambling to pay huge living expenses.
I wrote about my experiences on my own hubpages if you are interested in reading more about it.