Vogue magazine did something interesting with shopseptembervogue.com. Site visitors could buy certain styles featured online by clicking a "buy now" icon on an advertiser's online ad, assuming the ad was set up for electronic-commerce or linked to an e-commerce site. Otherwise, the ads provided information about bricks-and-mortar stores where the featured items could be purchased.
It reminds me of an entry that John Battelle wrote earlier about "endemic advertisers" - advertisers that 'fit' within a publication's community. Shopping centers do it all the time with their tenant mix. You're not going to find a Wal-Mart in Rodeo Drive anytime soon.
Imagine combining Vogue or GQ with Rodeo Drive's web site. What stores in Beverly Hills carry the products advertised in those publications?