Jackie, have you ever had the possibility to read on an eink reader? Or do you have the possibility to try one in a shop?
The reason I am asking is that maybe you don't need the "white letters on a black background"-feature. There are quite a lot of people with eyesight troubles that have big problems reading on lcd screens and no problems reading on eink screens. But I don't wanna influence you in any way - you know best what's best for your eyes!
And welcome to MobileRead!