Re: Recurring Billing/Auto ship module
@HeleneWallis, Thanks for the site link.
I looked over the site and while they are facilitation "Recurring" orders, I'm guessing it's not programmatic. They seem to have two versions of their products (one for one-off orders and one for recurring) VS giving recurring as a product variant which is a cleaner solution. If he gets back to you it'll be interesting to see if he is tracking the recurring orders manually. I suspect he is.
If manually tracking is an option for you this might be a decent short term solution.
That being said, a robust and secure programmatic solution is doable and something I'd be interested in working on. It just needs time and funding.
Re: Recurring Billing/Auto ship module
I took a look at the vitamin website too. If you look at the product details for their "cancel automatic shipments product", they're just saying for people to leave an order comment for what subscriptions to cancel, so that's manual. They also have an update posted in that same description that says you can now cancel from your account page. That mentions that the subscriptions are managed by some other external system, so ZC is not very directly involved in any part of their process.