alt Hacker NewsI've been hoping someone would build the same thing. Even without delivery, I'd love to be able to search for products across multiple stores through a web interface and see their availability in a map view, with price and in-stock status. I would be happy to go to the store and buy it, as long as I only need to make one trip and I know it will be in stock and at a certain price.
I worked on this, it was called Milo.com. we had crazy scraping and xml/csv feed ingestion. It was a terribly difficult business because most retailers hated us. ebay bought it and eventually killed it.