The way it looks I wouldn't be too shocked if we close iOS 5 on 5.1.x. WWDC is coming closer by the hour and so is iOS 6. Thinking back iOS 3 was capped at 3.1.3 for iPhones and iPods so this thing has happened before. (and will happen again )
I'm content with iOS 5.1...As for wanting another beta, I was the same way when I had my Android devices. I flashed every rom under the sun at one point and I was always eager to try the latest update, but I got all of that out of my system.