Popping in with another suggestion for those who are willing to try the unusual...
American Ingenuity makes a series of Hi-R insulated geodesic dome homes that can be bought by the individual and built into a very air-tight and awesome living space.
http://www.aidomes.com/
Don't forget to consider their smaller 12-foot Pod storage dome. It would be cheap enough to use as a starter dome. I think the price is somewhere around $750, and can go up to close to $1000 depending on the options you add to it. For 110 sq feet, it's a great deal, and it has an insulation of R-8. Here in South Texas, a storage building with R-8 is a good deal!
I was thinking about getting a few of these Pods, and linking them together to create a larger living space.
http://www.aidomes.com/index.php?option=com_content&view=article&id=385&Itemid=448
Another company makes prefabricated fiberglass panels insulated with styrofoam. The panels can be bolted together easily, and I believe they have quoted an assembly time of like a day or so for a medium-sized dome, with four people assembling the panels.
The smaller dome is about 333 sq feet and costs about $8500 or so.
http://www.domesintl.com/housesplansprices76pg/domehousing72.html
A larger one is about 777 sq feet, and costs a bit more, but is still below $20k.
http://www.domesintl.com/housesplansprices76pg/domehousing54.html
These Domes International domes used to be made in Mississippi - not sure where they are now... they have changed up their website and it is difficult (for me) to manuever.
I also know of a fella who has taken the concept of the monolithic EcoShell domes, and has used papercrete, styrofoam and cement, and has made an awesome highly-insulated and easy to use building material that is strong and environmentally friendly. A few years ago, he was quoting building a 20-foot diameter dome for around $5000 - which is a very good price for about 315 sq feet of floor space. Using styrofoam and papercrete, the R-value of this would certainly be upwards of R-20 or so.
I am also working on home plans to link several of the 315 sq foot domes together to create a much larger living environment.
There are many more domes that I have looked at, some cost more than others, but the above three seem to have caught my interest above the others, as having the highest R-value, the lowest cost, and the most practical.
Anyway... don't mean to hijack the thread, but yurts are not the only way to create a living space.
Regards,
Jim TX