I have found that spelt flour (you can get both white and whole) can be substituted for all-purpose flour in anything I make, and does not bother my type O husband. I have also had no problem substituting soy milk for milk in baking. Butter is a neutral for O's also, but it's an avoid for me (AB), so I use a substitute that has no trans-fatty acids or hydrogenated oils if I need a solid fat. (Email me if you want the name). Most of the time, I substitute olive oil (extra-light for baking sweet stuff), or grapeseed oil. With spelt, you just have to use less liquid (about 3/4 of the amount you'd use for all-purpose flour), but use the same number of eggs. I don't even use all-purpose flour any more, and my husband says things taste better. It seems that spelt doesn't interfere with other flavors (chocolate, lemon, vanilla) the way regular wheat flour does. (Anybody else find this to be the case?) So, perhaps you could bake a carrot cake substituting for the avoids, and.... oops, I was going to say "have your cake and ..." - oh, never mind.
Also someone on this board posted a recipe for almond cookies, and brownies, using no flour. Haven't tried them yet, but I intend to. They sound outrageously good!
While I'm at it, thanks to all the knowledgeable people on this board - you have been more help than you know!