I've just posted a new set of instructions which explain how to get Amazon Instant Video on most Android tablets. You have to install a couple apps and configure them, but once you've done that you can stream video from Amazon.
I've tested this on a few tablets, and there are reports from TeleRead which say that it works on a lot of tablets. But do you know the best part?
I found a way to get this working on my Nook HD+. Yes, I undercut my single biggest gripe about this tablet, and had to go revise my review.
On a related note, this trick is probably going to force me to revise my review procedure; I have found that this makes an excellent stress test which will help me rank a tablet's media abilities. For example, the Hisense Sero 7 Pro had trouble keeping the audio in sync with the video. The Nook HD+, on the other hand, didn't have nearly as much trouble.
You can find the instructions here.