If you are planning on doing this at your school there are a few things I would consider first.
1. Don't leave it up to the students to construct the playhouses. Have a contractor (or a handy group of dads) do the actual building, and let the students decorate them. Painting and furnishing the house is tons of fun and will be more than enough for the students to tackle.
2. Keep the houses small enough to easily transport.
3. Give the students some direction. Themes are fun and can tie into the spirit of homecoming.
4. Have an adult inspect the playhouses and furnishings for safety hazards after completion. See the safety check list.
Images can be found on the School's site.