Hi Dave,
I have been asked to design them a few times, have been part of a couple builds back in the late 70's and early 80's, as well as, observing them through the decades. In concept...wonderful...in application...well, that is often another story...
If you decide on a kit...(if they are still making them someplace??)...make sure the company has been around at least 30 years...NO LESS! Seen this happen way too many times...Kit goes up...leaks happen...then other issues...company gone and out of business.
As for building yourself, any PE can approve an adequately detail CAD and blueprint for one. The issue is whether they will put their licence on a line for one in the realm of "leaking" and/or perhaps some other challenges they are plagued with.
Some folks (not too many) just love living in a "dome home" style...challenges and all. The examples I know of that are the most successful (fewest leaks and challenges) are basically a
wood armature that supports a urethan foam inner and outer shell. Insurance and resale, can also be a challenge in some places.
Good luck with your search and build,
j