You can grow even larger squash and the like on a trellis -- as long as it's a very sturdy trellis...
Years ago I tried growing 2 of the 3 sisters together -- corn and squash/pumpkins. Trying to harvest the corn was quite a mess... it later occurred to me that the "3 sisters" planting would originally have been with beans intended to be used as dry beans (not snap beans), corn intended for grinding into corn meal or whatever (not sweet corn), and winter squash. That works because everything gets harvested at the end of the growing season.
