The Amiga community have been asking "Amiga" Inc for things for years, and they have failed to deliver anything. As with most other things on the Amiga, you will have to do it yourself. Look
here for an Amiga 1200 keyboard and a Keyrah, which will convert it to USB. Then you just need a casing for it. You could either use an old gutted A1200, or maybe another Amiga keyboard is physically compatible.
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moto