What's the best plugin config for a physical goods subscription model website?

Hi all,

Trying to get some advice from the more experienced members on this. Any help or tips offered are highly appreciated.

I am planning to set up a physical goods (i.e. non-digital) subscription based e-commerce website. This is conceptually similar to e.g. Birchbox or Graze, where members get monthly physical deliveries to their door. The crucial functionality I need is:

- 3 tier membership;

- memberships are time defined (similar to WPMU Dev's 1/3/12 month memberships with set pricing), as parcels despatched on monthly basis;

- recurring billing dependant on membership (i.e. every 1/3/12 month(s)), member has ability to set and change specific dates for delivery (e.g. every 15th of month), ability for consumers to upgrade/downgrade/renew memberships, ability to manually extend/shorten memberships by admin;

- no difference in viewing actual content on site (so different to a plugin that restricts access to parts of site depending on membership) but difference does exist in terms of which / how many products can go into delivery (see below);

- here's the crux: upon paying for a membership tier, customer has access to a predefined set of products to choose from that will go into his/her monthly basket delivery (to take Graze as a reference: consumer chooses box tier; consumer chooses X number of nibble types s/he likes from a tier-defined list of nibbles, consumer thus creates a basket of goods they want delivered; consumer has ability to freely change the types of nibbles they want in their box from month to month but, again, within a confined set of choices);

- backend stock management. Unless I automate calculations of which products I need when, keeping the right stock at the right time will be a planning nightmare;

I think the tricky part is actually conceptualising how to combine a typical e-commerce offering (i.e. full list of products that can be put into check out cart and bought in one delivery) and a subscription (i.e. set pricing tiers for given access) in order for members to create their baskets from tier-defined sets of products (e.g. certain brands/products available only in tier 3, different number of products allowed to be placed in each delivery). This is slightly different to having a customer choose any products completely freely the first time round with an ensuing auto-ship feature thereafter. The other big problem, as mentioned, is stock management.

I am aware of the existence of the MarketPress and Membership plugins but still trying to get my head around as to how to fuse them together, or with some other plugins to really nail the functionality list above.

Pheewww... Tried to be as specific as possible. Hope this helps and hasn't scared anybody away!

Any suggestions as to which plugins and how to make them work together to achieve the above would be greatly appreciated.