Wow! I love your commercial idea! Where do you have the bins now? What do you feed them? Harvesting??? Whew!
I live in an apartment and have 4 bins going, and have NO idea what to do with the castings. Just give some to friends I guess (I have done that already).
I'm hoping that we'll be able to purchase a house in the not-to-distant future, and have plants to expand my herd and help people get started in vermicomposting.