If you are worried about school lunches I would sit down with the school dietician and head cook at the lunchroom NOW and talk about your childs needs. They will be making their lunchroom budgets now, if they already haven't and will need to know what to purchase. Possibly they could keep a few items on hand that he could purchase to suppliment his lunch from home. Maybe a bag of safe chips, or a cookie or juice box that would make him feel special still and buy from the "restaurant"! ha that is too cute!
People with Celiac Disease are covered under the Americans With Disabilities Act, so the lunchroom, does have to supply your child with an appropriate lunch. If you choose to go the lunchroom route.
Some lunch ideas that I take for my lunches: (I am a teacher)
Gluten free lunchmeat with cheese in a roll-up style (sometimes add lettuce)
Cold Cheeseburger (no bun) just ketchup to dip in
Jell-0 and fruit cups
Applesauce cups
gluten-free Chips
Doritoes (NOT nacho cheese)
Cheetos
Fritos
Corn Chips (mission)
Frito lay chips (read labels)
gluten-free Homemade cookies (make a batch and freeze in packs of 2)
Most of the time I make extra of whatever I cooked for supper and use a school microwave and warm up my lunches. I am sure that if you asked, the cooks might be happy to warm up lunch from home for your little one. This seems to be the best option for me personaly because I get bored with lunchmeat easily
Also in reguards to the staples of a 6 year old. DeBoles makes a rice pasta and cheese in a box (like the cheapie Kraft box) however DeBoles is not so cheap! ha It doesn't taste bad at all.
For chicken nuggets, I bread chicken breasts cut into pieces and fry them, makes healthier yummier chicken nuggets. There is also a company that makes gluten-free chicken nuggets....can't remember the name of them right now I am sure someone on here knows the name.
You could always do PB &J on rice cakes, not quite the same, but better than nothing

Oridea french fries (most plain ones with no seasoning) are gluten free, just read lables.
There are several good gluten free cereals out there. Peanut Butter Panda Puffs by Enviro Kidz (nature's path) are awesome. Enviro Kidz has a line of gluten-free cereals that are really good. Also mainstream...fruity pebbles are gluten-free (some worry about cross contamination with these, I have had no problems so far).
Kinninnick offers some great gluten free doughnuts. You have to order these online. They are not light and fluffy, but sure do make a darn good replacement when you are craving doughnuts.
http://www.kinnikinnick.ca/I wish you and your family the best, you have found a great support group here with these people. Visit often and ask questions!!
Best Wishes-
Jessica