[samch]

I’ve backed this product, the Flux Keyboard, on Kickstarter - it allows for the type of dynamic changes that the author is describing in case others are interested:

https://www.kickstarter.com/projects/fluxkeyboard/flux-keybo...

[wlesieutre]

Similar setup to the Optimus Popularis around 2011

https://www.tomshardware.com/news/Optimus-Keyboard-LCD-Scree...

Before that they had some designs with little displays in each key, instead of a big display behind all of them