It will nearly be impossible to find a nut, egg, wheat, soy, bean and rice free product out there. The milk substitutes are made with rice, soy, soy/wheat, hazelnut and almonds as are all dairy substitutes. There is Dari-Free which has lactic acid but is rice and soy free.
http://www.bobsredmill.com/index.php
Has gluten free flour for making at home bread and other baked goods.
They have things like date sugar, cornstarch, flour and other baking needs. Like most places they often use beans or rice as a substitute but the flour, date sugar, maple sugar, cornstarch and grits all are gluten free and purely that item.
I never tried this company which sells dry mixes.
http://www.chebe.com/dryproduct.htm
Ingredients: Manioc (tapioca) flour, modified manioc starch (100% manioc), iodine-free sea salt, cream of tartar, sodium bicarbonate.
http://www.clanthompson.com/res_contacts_shop.php3
A list of companies making gluten free items. I spent nearly an hour cllicking on links.
I am not sure about cross contamination but I use corn tortillas which usually are guaranteed on the label as gluten free. Mission probably. Lays plain chip, Fritos, Tims potato chips, and some Oscar Myer cold cuts.