years ago I played D&D with my friends. we played the Dark Sun campaign setting. In this world the halflings were master bio-engineers. through a process incorporating both horticulture and animal husbandry, they used the building blocks of matter to create organic and even living items. I don't know if it would be possible or even worth the effort but it would expand greatly on your bio-engineering system. if you would like to know more or have any questions let me know.