Working with partners.
I'm unsure how the details would work. Possibly offline transactions or with having an escrow account somewhere holding bitcoins. The two leading merchant vendors for taking bitcoin payments are currently Bitpay and Coinbase. I would start with them to see what they have to say.
American Express did a survey last week for all american express corporate and business card users. They were asking for technological innovations amex should invest in. I wrote the NFC Ring in the comments. They do not really support bitcoin in my understanding, but they have a prepaid debit card, which could maybe be replaced by the nfc ring. As it seems they are really searching for new markets and technology, you should contact them.
regards from Germany
I second the motion to work with Coinbase and BitPay. Both are reputable organizations with great service.