Interesting idea. I made an attempt to vet a similar idea in the spring of 2009, so maybe my experience can help you out: In order to prove or disprove the concept without actually building out any kind of CMS or infrastructure, I set up a marketing site and some demo restaurant mobile sites (really good looking stuff built on jQTouch). Next step was to build prospect lists with every OpenTable restaurant in a handfu…
Thanks for your feedback! This sounds precisely like what we're encountering right now: restaurants are uncertain why people would want to see their site on a phone and how it increases their bottom line. We'd like to educate them and show them that customer discovery = ROI, but we're not sure how to evaluate that in our context. Some people here have suggested success stories, which we think is fantastic.
You could also offer to store a contact for the restaurant.
Google voice is free, each restaurant could use a call to GV as a way to track leads generated by your app.