Some insurance companies specialize in policies for properties of 3000 sq. ft. or above in gross living space. These companies are typically considered affluent market carriers.
Although these policies tend to be more expensive then their standard line counter parts, they include some really great coverage. Some features are guaranteed replacement cost, reverse liability, cash settlement, and deductible elimination. They also offer policies such as travel insurance and kidnap and ransom insurance.
With standard insurance carriers, it often makes sense to split policies between different carriers. With Affluent Market companies, that is much more difficult to do. They will typically require multiple policies. If the home is the policy that is desirable, you may have to add an auto, fine arts and/or a personal umbrella to qualify for the home insurance.