Any idea of ANYTHING I could say to his new teacher that would make things better and get him accommodated in some way?
Not sure this would help - but have you checked out the appeals process for the GT application? We were able to add more info to our ds' application and this resulted in him being accepted.
He was pretty sad about school when we started the whole process and when it finally came through, it has really helped turn him around on the whole idea of school. (keeping fingers crossed that this holds up!)
On speaking with the teacher, definitely approach with an open mind and set up a time to chat. Let him/her know generally what you are interested in discussing so they are not taken by surprise. Let them know you want THEIR opinion on the best way to move forward - basically you need to butter this person up!

Keeping your son's interest and spirits up about school/learning needs to be your initial emphasis - possibly not even mentioning the gifted question, but use terms like very bright, used to be very interested in learning, used to love school, etc. Whatever you think will paint the picture of a decline in enthusiasm as a problem for everyone to work on. It won't be a pat, oh this will fix it answer, but you might move forward an inch at a time. Keep ds in the loop on what is happening, that you are still trying. Don't let him think you have given up! (I know you haven't but kids can get funny ideas!)
Applying to the private schools should help keep spirits up, at least for him, but do be cautious as squirt points out. We looked at a private gifted school but felt that, at least in our case, the public schools were doing nearly as well with differentiation and they didn't offer much in the way of visual arts and performing arts, which for now is our ds' greatest interest.
Lastly -
Is he involved in much afterschool/extracurricular stuff? This can be a real lifeline for kids whose needs are barely met during the regular school day.
Heck start your own after school club to keep him generally interested in doing stuff!
I say this with zero experience and almost no extra time (working mom) but have just volunteered to start a comic book making club at our school.
Not even sure it will get off the ground, but ds is totally into this sort of thing right now and I think it *might* be a great way to pull together a group of like minded boys/girls for a fun hour or two every couple of weeks. We have the added incentive of there being no established clubs yet at this new elementary school so maybe we've got a shot!
Anyway, best of luck to all in your family
