This occurred to me today, and I think they could be the perfect suitor for WebOS. They have already snuck into the tablet market sideways. But because they haven't taken the iPad head-on, it hasn't gotten much hype.
Amazon has already shown some displeasure with Apple's royalty practices. Amazon had to drop support for buying books directly from the iOS Kindle app. I have heard Amazon may drop the iPad app altogether, and just have iOS use the browser. Amazon has their own app store on Android that competes with Google's. Yet Amazon was one of the very few companies to embrace WebOS with an app for the Touchpad launch.
Making WebOS the platform for future Kindles could make a lot of sense. The fire sale has proven people want cheap tablets. The market is ripe for a product using the "give away the razors, make a profit on the blades" model. HP couldn't do this, they had no blades (apps & content) to sell. But people go to Amazon wanting to buy content. A Kindle could become a platform for selling books, music, and videos and more.
WebOS would be perfect for this. It comes with an excellent Flash-capable browser, much better than the Kindle's current one. Kindles have hardware keyboards, which would make good use of "Just Type." WebOS would also give them some apps. WebOS doesn't have a ton, but a Kindle doesn't need an app for every single thing under the sun. Basics like e-mail, weather, Facebook, Twitter are ready to go. Leave home security and remote-control helicopters to the iPad.
BUT, if Amazon sees the light and decides to take this on, I wouldn't expect it to be roses and sunshine for the WebOS ecosystem. Some bloggers have said WebOS is tainted, it's a loser, and associated with failed crap. I think that's unfair, but I can see how people would think that. Nobody cares what OS runs the Kindle now, and Amazon may want to keep it that way. It may just end up with a little "Powered by WebOS" logo on the box. They may even change the name. Amazon may not care about non-commercial apps, or they may not care to facilitate homebrew.
But at least WebOS would live on to fight another day...
So Jeff Bezos reads this forum, right?