This was an aftermarket keyboard for the A1000. A couple of guys in Portland, OR had these on the A1000s.
Do u know who made them or sold them?
It really looks like something some guy threw together in his garage using the parts he had on hand.

What are the advantages of that keyboard over the original A1000 keyboard?
Does it have some keys that are missing on A1000 keyboard?
I gave my A1000 away about 20 years ago so I forgot all about it.