The basic concept is to purchase a set of plans "off the shelf" directly from an Architect, and then work with them to customize that plan to your specific needs and tastes. The two images below depict a house designed by Ron Brenner Architects in Stillwater, Minnesota.
It is a beautiful Cape Cod design.
The client loved the design inside and out. But the plan would not fit on their own lot configuration, the room arrangement did not satisfy 100% of their needs and their aesthetic tastes tended more towards the contemporary. So Ron Brenner Architects sold the plan to them for a flat fee, and then worked on an hourly rate basis to modify the plan to reflect their needs. The images below reflect the modified design.
The client loves the new design and they were able to reduce the design schedule and design costs significantly. The house is now under construction - I'll update this post with photos of the project when available.