I stumbled on a way to make (mostly) allergen-free sandwich bread!
I started with this recipe: http://www.grouprecipes.com/101267/gluten-free-yeast-free-pizza-crust.html.
I’ve been making it for a while with a rice flour/potato starch/tapioca starch mix at 3:2:1 ratio, and while it needed a bit more flour (or less water) it made an awesome yeast-free pizza crust/foccacia bread. I changed my flour mix to 1:1:1 bean flour/potato starch/tapioca starch, and the mix was even more soupy, so much so that when I baked it, the edges were thin and crispy like a cracker.
The next time I made it, I actually tried to make it thin enough to be a cracker. Instead of my round stoneware pan I used my rectangle stoneware bar pan (it has an edge), and I poured the batter so it filled the whole pan. It raised nicely – just to the thickness of a slice of bread. So I cut my rectangle into bread-slice-size squares, and voila! Sandwich bread that is wheat-free, egg-free, yeast-free, corn-free, and dairy-free!
It’s thin enough to put fillings in and still get my mouth around both pieces of bread, thick enough so that it’s not crunchy, and firm enough not to fall apart while I eat it. I don’t think I’d ever have thought of baking sandwich bread sideways, but there you go! I’ll have to try for crackers another day. Right now I’m enjoying my sandwich way too much!