My friend's daughter thought my 3D printer was cool and said she wanted to make her 4th grade California Mission project on it. I told her if she designed it, I'd print it. She spent a month learning TinkerCad after school: dutifully taking the online tutorials... I had to deliver on my end and ran my printer for 16+ hours... and here's the output! (The roof is two colors because I ran out of red while printing...)
The bell is the only thing she didn't design http://www.thingiverse.com/thing:5015.
This is not based on any particular scale. She tried to be roughly consistent on proportions using a ruler on pictures and Google Earth and eyeballing approximate ratios. Perhaps the biggest lesson she learned was how to break down objects into basic geometric shapes (both the presence and absence of them) because of the way TinkerCad works.
This could become a cool twist on the California Mission Project all 4th graders do if I could involve the math teacher and really explore ratios more deliberately. I might explore laser cutting some walls through to speed production (16 hours of printing per student won't work!)
Given that I had a Replicator 2X and the length she'd chosen was 12 inches, we printed the side walls in two parts. The back wall is also repeated and used inside for internal structure for the roof. The roof was one of the first things she designed so we had to print three of them on each side for proper scale once the overall length was figured out.