I don’t know, really huge demons do wonders as living siege engines and spreading terror on battlefields. I certainly have read about such types, although they do tend to be the stupid types and they are often created and/or bread by fellow demons and mad wizards.
Note btw that if getting children is the prime goal, then you actually would prefer male scubi. Sure, they might not be summoned as much (which I really wouldn’t bet on since in general at least on Earth woman tend to be really frowned on when having sexual relations beyond that of their husbands, and no scubi is going to blathermouth), but one male can impregnate a lot more woman then the other way around. Myths on low-magic worlds also tend to depict women more often as demon summoners, but that I blame squarely on male propaganda 😉