I think if I subbed green beans for the limas, I would use more potatoes to thicken it a bit. The limas I use are the large Fordhook ones that contribute to the starchiness/thickening.
Chowders seem like they are really versatile. You can do them with just one or two ingredients. I really like blending the corn because it looks so much like there is bu**er in it.
Another thing I do with The Meat Eater (TME, our youngest son) is to do burrito meals, or sandwich meals. I put bowls of food on the table and include either taco "meat" which has rolled oats added to stretch it out a bit, tee hee, and maybe some cheese but often I "forget" to buy cheese. Lots of other stuff that he likes though, avocado is a new food he will eat. Corn, beans, onions, tomatoes, salsa, hot sauce, avocado, lettuce, shredded cabbage with garlic vinegar.
For sandwich meals, it's onions, peppers, all kinds of pickles, sliced beets, tomato, lettuce and then a little bacon or something. Just a LITTLE bacon, and he now knows that he can have more bacon if he has a SECOND sandwich. Sometimes I do a sandwich spread with garbanzos.
Spaghetti is nice, too. You can make meatballs with oatmeal to stretch the meat out a bit, bake or pan fry then put half in the freezer for next time. Serve the meatballs on the side with your nice marinara and whole wheat noodles, or brown rice noodles that are whole grain.