Whispersync for Voice (syncing between e-books and audiobooks) is live *now.* It works (obviously) with older devices. It works with my Kindle Keyboard. There are also a variety of free books/audible books you can try it out with. I used "Dracula."
Here's a link to the page:
https://www.amazon.com/gp/feature.html?docId=1000827761