As of 2016, ePlans and Cool House Plans offer house plans with mother-in-law suites. Both of these places are online resources with blueprints for sale.
EPlans offers more than 500 plans for homes that include mother-in-law suites. These plans include house styles, such as contemporary, prairie, craftsman, European and new American. Customers can filter the results by number of bedrooms and bathrooms, square footage, layout and special rooms.
Cool House Plans provides more than 150 floor plans for homes with in-law suites. A customer can click on a link to see the floor plan from each entry's photo. Each of these plans has two master suites built into the plans.