Catalina and Hunter IIRC both have what I would call sailing "Dinghy's" for four folks. As does Vanguard, the current builder of lasers/opti's among other boats. An old C-lark was 14' long, 4 folks of smaller size could fit and sail in it for an afternoon. BUT, I would not call a 12-16' boat as "I" would want for four folks to enjoy a sunny afternoon or evening sail a "Dinghy" A dinghy to me is under 10'.
Another option on the west coast, is Gig harbor boats. They have boats from 8-16 in length, most based on wherry style hulls. CLC linked above, has a 14' wherry that would make a neat build your own, as does Pygmy boats in Port Townsend Wa.
Glen-l and Clark Craft are two other places to get plans and kits for boats of all different sizes too.
She drives me boat,
I drives me dinghy!