Wow, thanks for the replies. There is so much I don't know about food and how it can affect people! I had wondered what the guar gum in the 'free-from' section of the supermarket was for... I guess I need to do some more experimenting.
The garbanzo bean (chick pea, gram) flour does taste beany to me, though it is in a lot of Indian sweet dishes. I have used it added to plain flour to give an exotic taste to reduced-sugar cakes for my diabetic father, but the effect is not quite the same with rye or buckwheat flours.
My daughter is okay with gluten, but I thought that spelt, being a form of wheat, might be risky with a wheat allergy, so I have not treid it. My understanding was that people who have developed an intolerance to gluten from eating store-bought bread made from wheat bred to have unnaturally high levels of gluten, which then has more gluten added to make it fluffy, can eat spelt because of the low gluten content, but that if a baby has an allergy (ie. has not had opportunity or cause to develop intolerance), then all forms of wheat and its close relatives are suspect.
Though my understanding of what constitutes allergy or intolerence is pretty sketchy. I have bought Doris Rapp's book, but have yet to read it, and the pediatrician was not willing to give me any advice unless we consented to have our still-nursing two-year-old admitted overnight for clinical food challenges, onefood at a time. We figured the fact that certain foods consistently make her ill was enough evidence for us not to feed them to her, with or without a diagnosis.
I do have one wonderful chocolate cake recipe (for occasional use as I'm not so sure of chocolate) using sweet potato and beet, and I'd love to try more similar ones.