Yes, I've had experience with NAET. A little over a year ago, I was as desparate as you sound. It seemed I was reacting to everything I ate (headaches, asthma, GI symptoms as well as a host of other things). I had been tested several times for food sensitivities (Alcat and Immunolabs) and had been following all kinds of rotating diets without success. Interestingly, I have always tested negative for gluten sensitivity by antibody tests and small bowel biopsy. When I saw the NAET practitioner, I was limited to Metagenics “medical foods” and a few vegetables (alas, the “medical food” is all rice-based!). I tried NAET on the recommendation of a friend who had had some success although it didn't last for her.
When I first saw the NAET practitioner, I noticed that my stomach was calmer, but not much else. I was, however, able to reintroduce a wide variety of foods as long as I continued to be treated. I never was symptom-free, though. I continued with asthma symptoms and headaches. I stopped treatment in the summer as we traveled to New York, and all my symtoms came back within a matter of weeks. So, bottom line is that it didn't last for me – a similar result that the friend who suggested it also experienced.
I've now been grain and dairy-free for about 2 months and I'm feeling as well as I have in years. The headaches are gone, and I've been able to stop my steroid inhaler. I hope you have similar good results with your grain-free diet!