@AntonyTerence i only made a proposition as to have it as an accessory because not everyone want this and then depending on the price it could be a blocking factor for some people.
When you look at the bottom of some laptops you can see 'doors' to access the memory/hard disk/..., you could imagine having the same under the base keyboard allowing you to plus the e-ink screen in it if you decide to buy the option.
But again this solution wouldn't be nice because you would have to put screws to securely attach it and that wouldn't be nice.
You want this included in the thicker keyboard but then will you still be able to have the tablet like on the photo I posted in the first post ? you have to think of the weight you are going to put on the kickstand hinges. Maybe it wouldn't be a problem but maybe it would be.