You forgot Google. They have Motorola, and they are going to be highly integrated with Android, no matter what they say in public.
Also Samsung has gotten pretty integrated with Android, too. Sure they add the latest "Android features", but on their own time, and it's not the main priority for them. They'd rather ship with an older version but filled with their own apps, features and technologies. It's not that different from Amazon actually, except that they still have to adopt some standards set by Google to make sure they don't fragment to ecosystem too much, but they also get the benefit of access to the Play Store and the Android community (Amazon doesn't appeal to the Android community as much anymore).
Right now, Samsung is Android to a large degree. They're the only Android phone vendor that's actually making money, and they're selling a ton of units compared to the other vendors.
I'm amazed RIM has lasted this long. From what I've read I'm pleasantly surprised. I know there is still a small minority that refuses to own a phone without a physical keyboard, and the few I know aren't very happy with the few Android phones they've tried with keyboards. They may be able to get enough of a niche there to hold on and survive a bit.