like i said, as far as business goes there would be a lot to work out, you'd need cheap ammonia, cheap media, etc... as well as the space to keep tanks and stuff.
but if it will work in theory, and even in practice, then there are companies out there which could offer it.
i my LFS had offered to sell me enough mature media to fill my filter for £30 when i got the tank, and told me it would mean I could stock my tank almost immediately, I would have happily paid it. would have been a bit moreprofit for them, and they probably would have also had more fish sales from me, since I would have got all my fish from them before I spotted the disaster that was the betta tanks...