Not as crazy as it sounds. With RAIN Rfid you can get the xyz location of a tag from ~30ft away accurate to 6" in realtime.
Examples: https://www.youtube.com/watch?v=p1LykdRWTfk https://www.youtube.com/watch?v=-hCA8L7v-R8
Examples: https://www.youtube.com/watch?v=p1LykdRWTfk https://www.youtube.com/watch?v=-hCA8L7v-R8
What is really needed is a way to talk to multiple RFID tags quickly without any crosstalk. Think of a handbag with a dozen candy bars in it. How do you scan them all quickly without missing any?
The goal has always been to scan something large in one pass, say a shrink-wrapped pallet of items that could number in the hundreds or thousands. Obviously this is technology that Amazon could benefit from as well, I wouldn't be surprised if there's a lot of technology overlap here.
Most RAIN Rfid readers have a read rate of 800+ tags/second. Door portals are a solved solution and now phased arrays are on the market which scan all items in realtime. Take a look at the impinj marketing material for more information. For example the RS2000 chip: http://www.impinj.com/products/reader-chips/indy-rs2000/