This is probably the best idea ever. The first time I ever had it was at Loki's house, years ago, and I didn't ever recreate it, which is kind of odd, because it's super easy, and super delicious. The basic gist is divide your pizza dough into "individual" or small pizza portions and roll them out relatively thinly (You want it to cook through before it starts to char). Put the dough on a piece of tinfoil that has been generously coated with cornmeal. Put toppings on dough. Carefully put tinfoil and pizza into the bbq that has been preheated to 450-500F), close the lid and check it EVERY minute (it takes between 3-5 minutes depending on the dough's thickness. Use metal tongs to check to see if it's done or not. If so, pull the pizza and foil onto a plate with those tongs.
We did this as a pizza bar so everyone made their own pizza. In most instances the cheese melted as fast as the dough cooked, but you have to make sure the toppings and cheese are spread evenly: a mountain of cheese won't melt.
I particularly like this method of cooking pizza because you're not heating the house on a hot day, everyone gets to pick their own toppings, and there's something extra delicious about charred little bits of dough.