Not sure if this is a re-post, but there is a initiative underway with multiple companies collaborating toward the Future Store in Brussels. The movies on the site are well worth watching. I'm not too sure how far away this is, but seems that most of the technology already exists to make this initiatve happen.

Edit: This store is online and running now! It has many of the items and technology advances that the Walmart case offers. Here is a listing of the technology that the store uses.