I've thought about this a lot actually.
I would start a peanut/tree nut free sweet shop. It would be completely peanut and tree nut free (so safe from cross contamination).
Also, there would be egg free products as well (In addition to products with eggs)
I am allergic to peanuts (anaphylaxis) and to eggs adn am sensitive to tree nuts and I hate that most of the time, if something is peanut adn egg free, it is also vegan.
I make everything under the sun for desserts (choc. truffles, pretzels, peppermint patties, cakes, cupcakes, cookies, banana breads, muffins, etc) and everyone always loves them so I have thought about this before.
Everything I make is egg free and made with peanut/tree nut free ingredients (no cross contamination).