Christopher,
I have been running a Design/Build company with my contractor/husband/business partner for 14 years in rural Wyoming. We carry both Liability Insurance for construction and E&O for design. Our E&O Insurance has a "design/build rider" (and yes, it costs more). Our bonding agent explained it through the eyes of the insurance carrier: with d/b, there is no finger-pointing for who is going to pay for mistakes! This is great for operating a business and getting projects built with minimal hassle, but the insurance companies don't see it the same way. We started out with residential work and moved into public commercial work with a gas boom in our area, and not a single claim on either insurance.
-------------------------------------------
Bonnie M Chambers AIA
Principle
Chambers Design-Build Inc.
Pinedale WY
-------------------------------------------