So for 100, for entree size servings:

A little olive oil or vegetable oil to saute the onion
18-20 pounds ham or 50 ham hocks (the hocks are greasier)
18-20 pounds green beans
8-9 pounds onions, chopped
20 pounds new potatoes, small or chopped into pieces
4 gallons vegetable broth, or chicken or ham broth or onion soup (you will have some broth left after serving for future recipes).
Optional, 1-2 tablespoons sugar per pound green beans, 2 to 4 cups.
Salt, pepper, possibly a bit of garlic if you like it with ham.
Optional, I like some green herbs; marjoram, sage possibly dill

Saute the onion in a little olive oil.
Halve beans if they are large, add broth to barely cover, and add onion and ham or ham hock, cook covered until beans are crisp, not tender. Could be an hour over low heat (start high, turn to simmer as soon as it boils), or 2-3 hours on high in crock pots.

Add potatoes and cook about 45 minutes. If using ham hocks, pull them out while the potatoes cook, pick off and chop meat, and return meat to pot. Then cook until potatoes are tender, which takes longer if the potatoes are large.