My DH is a vegetarian as well and we just got back from WDW. We had no problem finding him food. WDW does a good job. It appears all table service restaurants have at least one vegetarian entree on the menu. Many times we would end up picking the restaurant by the veggie entree served. My DH likes to order off the menu, not a talk to the chef type. From other posters, the chefs are great making something to suit your needs.
Places we ate:
Boma - DH really liked it here! Lots of choices.
Jiko - Good Appetizers, Peas, grains and ?, - good
Plaza Restaurant - Veggie Sandwich (lunch)
Rainforest Cafe - Did this for the kids - Veggie Sandwich
Whispering Canyon - They had a good dish - it had changed since allears menu
Mama Melrose - veggie pasta dish without the chicken - good
Marrakesh - Veg. CousCous - just OK
Rose and Crown - A curry veg/rice dish - I think he really comes here for the guiness and the sticky toffee pudding! LOL
Kona - asian pasta dish (lunch) -
I didn't write down the breakfasts (CRT, CP & CM)they are easy.
Check out the menus on Allearsnet.com.