We're running a small test with essentially this approach. We're giving away the itinerary for free and then trying to upsell/cross-sell other related services -- such as a San Francisco CityPass, tours and p2p experiences. If you'd like to take a look you can check it out here (you'll have to enter your email address to get the free itinerary) -- http://bit.ly/enWxWz

My concern with partnering with restaurants and retailers is that I feel like it's a slippery slope to disingenuous recommendations. Plus, why would a restaurant offer a coupon to a traveler (at least a coupon of value)? There's no chance of repeat business. Just some thoughts, would love to get more feedback, if you have any.