I really dont like the keyboard layout of the Framework laptop, its similar to consumer laptops and Macbooks. Keyboards layouts should not be designed for appearance but for functionality.
You might not be familiar with the ThinkPad keyboard but when you have tried it you realize how useful and thought out the layout is. As well as the feedback and shape of the keys themselves.
The Page Up and Page Down above Left and Right arrow keys is an important detail (the big arrow buttons of the Framework is not practical and makes it really unergonomic to use them in conjuntion with up and down keys).
The position of Fn shortcuts are better than e.g. Latitude laptops (spacebar for key backlighting rather than F10 for instance). Also, the keyboards are just better to write on with fewer errors.
Personally I like the Fn position, even though it requires change of habit, there are advantages to having the Ctrl closer to the letter array.
So… what I am thinking is that the top cover is the easy part (there are different ways of achieving this, composite molding being one of them).
The real question is whether the cable has pin and signal compatibility with the Framework laptop. Does anyone know if the ribbon cable and its pinouts are standardised? Assuming that, should the Lenovo keyboard automatically be detected by the Linux kernel?