Or even just plan a weekly trip to the library and bring his book picks to school with you. That might be an easier sell than asking for the school to spend money on books that no other kids can read.
There's the risk that the library books might be damaged or lost, I suppose, but to me it would be worth that small risk to make sure that my son wasn't being damaged.
The bigger problem I see, however, is that of making sure the teacher gets it.
Have you checked out Hoagies for help? There might be some articles there that are written to help a teacher gain a greater understanding of GTness. I can't think of a good article offhand since I never found a situation where I thought that such an article would have been useful, but I'd bet there's something on Hoagies that could help you to communicate to the teacher what's happening.
