http://scalemodelplans.com/smp/pgs/catalog.html
Tom has a great collection of highly detailed plans built to import right into Model Builder. The plans are in .wmf format so you can have them as a workable background in Model Builder. As you add materials, the lines of the plans will stay visible.
As you may know already, there is the ability to change the color of plan lines. For this project since we are using dark bricks and roofing we chose yellow for the line color. After importing the plan choose "Plans">"Line Color"
A great step by step construction guide is included with any plan purchase too.