There s a budget bean enchilada casserole here;
www.ellenskitchen.com/bigpots/bbentree1.html
You could sub 20-25 pounds of chicken for the beans.
Stacked or as we call it in Texas, New Mexico style, is what you want.

spanish rice, several recipes for 100 on this site

a fresh fruit salad, see the fruit tray page, but I suggest you do fruit trays, look better, hold better, and any leftovers are more usable. Deluxe tray for 100 plus an extra watermelon (large) would be about right

menudo,
About 2 pounds of tripe for each 8 persons is what I use, honeycomb when I can get it. Honeycomb beef tripe is the lining of the reticulum, which is the second of the animal's four stomachs, and it really looks like honeycomb..
this is the recipe I use for about 120 people; you could do 1/2 unless you know for sure you have a lot of menudo eaters. This recipe is very garlicky; you can cut the garlic in half and still get a good result.

TexMex Menudo

The toasted, ground fresh peppers are key; some cooks use a combination of other peppers such as ancho, arbol, dried Hatch (hot) chiles. It's easiest to cut the tripe when it's partially frozen. Refrigerate this soup overnight and reheat the next day, to allow the flavors to blend.

Ingredients for 120 generous servings
For the meat base:
about 6 gallons of water
40 pounds of clean tripe cut into small bite size pieces and pre-simmered as below (about 1 inch. It's usually sold already cut up in pieces. A mix of honeycomb tripe and plain tripe is desirable. Strip off any fat before cooking.)
16 cow's feet or veal knuckles (about 20 pounds), this is where you would use the pig's feet
16 pound marrow bones (can omit if not available, but then consider using beef or chicken broth for part of the water)
64 large garlic cloves, peeled and minced
16 medium onions cut into thick slices
1/4-1/3 cup salt to taste
1/2 cup dry oregano
OPTIONAL 1/4 to 1/2 cup ground red pepper
OPTIONAL 1/2 cup coriander seeds
For the chili broth:
60 Guajillo peppers cleaned, seeded, open flat, and deveined
5 tablespoons of freshly ground cumin (optional)
48 garlic cloves
48-60 cups drained cooked hominy
For the garnishing:
1 cup pequin peppers crushed to add when serving if you like hot food.
48 limes/lemons cut into wedges
2 cups dry Mexican oregano
12 cups cup white onion, chopped
4 cups chopped cilantro (about 1 pound)
To be eaten with warm corn tortillas.

Some people soak the tripe in a mixture of 1 part vinegar to 8 parts water for about an hour before cooking.

Simmer the tripe for 1 hour covered with water. Drain off the water.

After you have started the tripe, in a separate pot, simmer the feet and marrow bones in a large pot with about 6 gallons of water, garlic cloves and onions for about 30 minutes at medium heat without covering. During this time, skim off and discard the foam that forms. Add the tripe and oregano and optional red pepper and cook for about 2 hours approximately until tripe is tender but firm (make sure you do not overcook). The liquid should cover all the bits- add more if needed.

You could also use electric roasters and set them on 185-200 degrees for about 6 hrs. Remember, with2 roasters, hey have o be plugged in on different circuits, which usually means different rooms.

Remove the feet and marrow bones from the pots. Skim the fat that forms on top of the broth. Once the feet cool a little, remove the bones and chop the meaty parts; return to the pot.

While the meat is cooking, prepare the Guajillo broth. Toast the dried Guajillo peppers on a griddle over medium heat. Press them down with a spatula, slightly toasting them without burning them.

Place the toasted peppers in a bowl and cover with water. Let them soak for about 25 minutes until soft. After that, process them in the blender in batches; drain the peppers and place them in your blender with the rest of the garlic, a cup of the broth, and cumin if using. Blend until very smooth. Strain the sauce using a sieve and pour into the pot. Add the hominy. Simmer the broth for another 60 minutes, partially covered. Taste to season with more salt if needed.
Serve the soup in large bowls and pass the garnishes; the lime and cilantro are really essential.

Do not forget warm corn tortillas to soak in the broth. 2-3 per person, with about a tablespoon of butter per person.

cotija corn dish (diced corn with mayo, cotija cheese, lime juice & butter),

25 pounds corn kernels
1 cup butter
2 heads garlic, peel ed and minced
12 cup cilantro, roughly chopped
2 1/2 pounds crumbled cotija cheese
black pepper to taste, 2-3 tablespoons
3 cups lime juice
2-3 cups mayonnaise