No mystery as far as I'm concerned. Amazon builds and sells many times the number of 6" Kindles as Sony does 650s. Amazon is the big buyer on the Pearl screen block. The manufacturer is going to bend over backwards to please a customer who buys a few million screens and treat a customer like Sony who only buys a few 10,000 screens like a lot less cordially. That is business and that is why Amazon is going to get first choice of 6" screens. The 350 has a 5" screen and the 950 has a 7" screen so Sony is not having to compete for similar sized screens with Amazon for those models. If B&N used Pearl screens in their eInk Nooks, the wait for 650s would probably be even worse.