Fourth graders in California (or at least SoCal since that's the area I'm familiar with) study missions and often make models of them. I know plenty of younger students who look forward to when they'll get a chance to make a mission. Personally, I really like it when teachers restrict their students to making "mini" missions. They're great because they allow students the opportunity to make a cool model of something without going overboard in terms of materials. Mini-missions also help keep the classroom clutter-free.
The fourth graders at one of my school sites just finished their missions--they were not mini-missions. I think their teacher wanted them to be able to focus on classwork without being distracted by their creations, so on Friday morning I received a phone call inquiring whether or not I'd be willing to display the missions in my library. Of course I said it'd be fine. Within the next fifteen minutes, my library was filled with missions; every flat surface in my library had a mission on it.
I still had classes scheduled to come in for their weekly visits so when the kids walked in, I made sure to warn them beforehand about the missions. Many of my kids have siblings who attend school with them. When one of my third grade classes arrived, one of the girls in the class pointed and called out excitedly, "Look! There's the mission I made!"
I said, "You mean there's the mission your sister made."
"Right...that's the mission my sister made."