If you find a house plan that you love, but want to make minor changes, most companies can have their designers do that for you, at an additional fee. It is also possible to have your plans reversed, for instance, if your breakfast nook faces west but the view from the north side of your lot is more attractive, you can reverse it. Many of the sites selling house plans will allow you to see a reversed view, of houses you might want to build.
Remember that plans are not necessarily "as is." Builders can use a reverse set of plans (sometimes called a mirror image) to better site a house. It's also possible to hire an architect or modification service to personalize a plan. Ask if reproducible prints or electronic CADD files are available for the selected plan. Either will make the alteration process quicker and easier.
Small house plans are normally defined as houses with less than 1800 square feet, excluding a basement. These house are also space efficient and less expensive to build on a small plot of land.
Every set of custom house plans includes several items which need to be blown up and detailed for further clarification. If a set of plans does not provide additional close-up drawings (for things such as beam connections, deck railings, stairway construction, etc.), then it is not a complete set. It is very easy to cut corners during the planning process. But the end result will be higher costs for the home owner - and lots of frustration for the building contractor.