Marc,
Maybe try to contact the advertising or promotions manager of Revell-Monogram or Testors or whichever company you wish. Use Scouting letterhead (if it exists) and write to them explaining what you want to do and what you want to accomplish.
I've seen a demo "build and take home" display by Revell here in Oz when I attended a model contest, where kids attending the show could build a pre-painted Snap-Tite Nascar (The wouldn't let me join in - I'm too old!! bummer) and it was a great success. Talk about forwarding the cause of modelling!!
The worst they can do is say no, or give you a discount. They might even say yes....You never know unless you have a go..........
Good luck and tell us all how you get on.
Cheers
LeeTree