The worst thing about the Sinclair Spectrum after it's audio and blocky graphics was the dead-flesh rubber keyboard.
That said, the ZX Spectrum keyboard has recently been revived as a bluetooth keyboard, designed primarily to couple with a Spectrum emulator on iDevices and Android, but I don't see why it shouldn't work as a general keyboard, if anyone was really interested in using it as such.
Well not exactly the same keys as the Spectrum per se, I am aware of the horrible ergonomics it provided back then!

maybe something that keeps up with the current times ergonomics-wise but still keeping the same ethos of having the cpu inside the keyboard. Then again might not be worth the effort. It's too niche I say
1. Because the designs are copyrighted. 2. Because Price (using less/cheaper material) counted more than esthetics, which counted more than ergonometrics (did the word already exist?) back then. Give me a cheap cherry keyboard any time over the cursor keys on the ZX spectrum (which are all in a line). (in general, keyboards were too high, having a computer inside. There were exceptions, like the Commodore 128D with a separate keyboard). But most were either flat keyboards, or too elevated.
The thing is you get used to the position of the keys on the keyboard, for example there are 3 types of return keys: those that look like an L those that look like the shift key and those who look like an advanced tetris form... you can get used to any of those.
There was also a new C64 case with a normal PC inside a year ago on kickstarter.
The philips' take on MSX2 computer had a same try on the keyboard's ergonomics; IIRC the keyboard itself can be positioned lower or higher:
But yeah, you're right: It's still quite an issue when designing it, either fitting cpu and leave the ergonomics aside, or ergonomics first but the dimensions all wonky

.
Maybe I'm just curious on today's technological advances how much better are we on able to do the best of worlds that we want (ergonomics/function/looks/etc), by just eke out each aspects to create something balanced!
I mean, just look at the new Asus' gaming laptop!
... Oh who am I kidding. I'd lose a lung carrying that thing
http://dilbert.com/strip/2001-05-31
Take NOTE, soon-to-be Pyra users! having EVERYTHING is not a good thing!

(or at least, make it light for your own good).
EDIT: Ah, sorry if I took the thread off course. Will do it less. Honest!