I would talk to the people that know everything there is to know about these:
http://www.monolithic.org/
The guy that runs/owns the place, David Brown, is a stand up guy. Our church was -THIS CLOSE- to building a dome for our church expansion.
I was the guy tasked with learning the pros and cons and making a presentation to the church leadership.
Your resale value will never be great, and the next buyer may have trouble getting financing.
I really liked the feel of the domes we visited...
Pretty much tornado proof, and potentially very
energy efficient.