There are some places around here that do this sort of thing all the time. That's where we got the idea. Only since this was a church deal to raise some money for a mission team going to Portugal the money goes to missions rather than the teacher.
I had LOTS of fun teaching and I have heard from several of them saying they want us to do this all of the time.
Here's how it worked.
I painted a picture to use as a model and to help advertise. It's 16x20 gallery wrapped canvas painted with acrylic paint. I didn't use my nice thick acrylic paints because I wanted to use the same paint they would be using (and it had already been purchased by someone else for another project). I was still pleased with how it turned out.