The cantilever design is indeed an elegant solution, though it can make it a little more difficult to hit the top row of keys.

I was thinking that this laptop is kind of like a Pi 400 + battery + screen. If we look at is this way, then what the OP wanted is kind of already available - you can buy portable computer monitors.

Interestingly, the Pi 400 + screen is kind of a "smart" keyboard combined with a "dumb" monitor, while the iPad Pro + Magic Keyboard is a kind of "dumb" keyboard combined with a "smart" monitor. It seems like both approaches have advantages and disadvantages.