There are quite a few vegetarian and vegan dishes in the book "Simple Foods for the Pack" by Claudia Axcell, Diana Cooke, and Vikki Kinmount, ISBN 0-97156-757-1. My edition is quite old, but you may be able to find it at a library or from in a used book dealer.
The group I usually travel into the BW with has included vegetarians in the past (although probably not this year). Here are some of the dishes that we have prepared in the past:
Breakfast - oatmeal, poptarts, bean (and or meat) burritos, pancakes,
Lunch - dried fruits of all kinds, nuts of all kinds, cookies, breakfast bars, peanut butter, dried seaweed, hummus, crackers
Dinner - red beans and rice, stir fry (meat optional), backpacker's pantry wild west chile (vegetarian), spaghetti (meat optional), jambalaya and gumbo (meat optional), instant pudding, tortillas with meat or meatless fillings to suit, veggie burgers, couscous, pizza dough, mushrooms, olives, other dried vegetables
I am sure that this list from our trips is incomplete, but may be enough give you some ideas on where to start.
You can get the Red Beans and Rice and the Wild West Chile from
(You need to Login or Register to view media files and links) online source. They have quite a few other vegetarian choices for quick (add boiling water) meals
-aj