point of sale + membership modules for a consumer co-op?

Hello,

We are working with a local food co-op, and helping them to migrate to a better POS/ERP system.

One crucial part of a consumer co-op is member management. Their user stories look like this:

- Set up a new member in the checkout line by swiping a pre-printed card with a mag-strip, entering their basic membership info, and getting them started (this could also happen at the customer service desk)

- Allow members to purchase store credit that can be used with their membership card (like a gift card)

- Migrate legacy membership data to OpenERP, and be able to generate codes for all of them to send to the card printing service, and allow them to pick up their new cards once they get to the store

- Give members portal access to pay their membership equity online (and if possible, add credit to their account)

We are aware that much of this can be done, aside from the POS system, given that we can test it. However, we don't currently have the means to test POS systems, card swiping and whatnot just yet. How much customization do you think it would take to interface the membership system with the point of sale system?