Hello, do you intend to deploy this Shed editor/configurator on the web? or is it a standalone application for clients to download? Regardless, I can develop the application using Unity3D where we can have complete control over shed 3d models so that values can be parameterized, values like dimensions, color, accessories, materials, etc.
From a control panel you would be able to adjust prices for every combination. Please let me know if you are interested in my solution.