Amazon's checkout-free Go stores might hint at the future of retail, but they're small locations that aren't much good if you need more than lunch or a bag of chips. You might see more soon, though. Wall Street Journal sources say Amazon is testing a version of its computer vision-based shopping technology for larger stores. It's not certain how close the company might be to trying this in the real world (it's currently running in a Seattle space "formatted like a big store"). It won't shock you to hear where the tech might go if it's successful, however.