There are many security standards you can "certify" your datacenter with, such as NIST or ISO. You can read more about them here: http://en.wikipedia.org/wiki/Cyber_security_standards

In addition there are some SSL and Antivirus vendors who provide "security badges" that can be embedded to your website and prove that your DNS domain and SSL certificate are valid.

Having said that, If you are serious about security and want to leverage that as a competitive advantage you would probably have to implement deep security measures.
You could then publish these measures in a whitepaper that can be shared with your clients.

You can refer to what Amazon have published regarding their AWS product: https://media.amazonwebservices.com/pdf/AWS_Security_Whitepaper.pdf

Guy

I believe the best way to do that what "mogl" does is by working with the merchants directly, in this case restaurants, and then cashback the customer credit card after a deal has been done.

From my experience as a PCI-DSS project manager for a large airline, issuers would not easily share their customers transactions even if they could.

Therefore I would challenge your question by rethinking on why do you need the credit card data? if it is for a similar use case as "mogl" or if you need the actual transaction for some financial app you may get access to that data by leveraging the "endpoint" of the transaction rather than the issuer.