Even if you put your own meals together or dehydrate, you can do vegetarian meals. I generally throw in TVP instead of protein, with plenty of stuff to flavor it (TVP takes on the taste of whatever it's cooked with). For instance, whether at home or on the trail, I use TVP in spaghetti sauce. Lots of Sarbar's recipes can be converted to vegetarian.

You can also cook up and then dehydrate dishes with various kinds of beans, lentils, etc.