I believe the case design came from Commodore's PC range, which was largely a German initiative. The A2000 was designed in Germany and never launched in the US - Commodore US designed their own system around a slightly reworked chipset which ended up as the B2000 (which used the same case)

To be totally honest, I have no idea what order things happened in there, but it would be very Commodore like to reuse the molds for the plastic that way.

We have never compared the C900 physically to the A2000 in datamuseum.dk, we should do that some day.