Have you tried the new self-serve checkout lanes at the Meijers stores in Michigan? They have two types, one when you buy a few items and one when you buy more.
Doing the job of a Meijers checkout person can be hard, frustrating work. Take all the times that the scanner malfunctions with the computer and you have to wave your arms for assistance. Then take the times when you buy a six-pack of beer or a bottle of wine and everything stops until the store employee comes to see if you're underage.
This supermarket in Germany has the answer, maybe. You use your mobile phone as a personal shopping assistant. You scan each item with your phone and then use the phone to check out. Looks pretty pain free with minimal frustration.