Hi,
I've got the guts from a KB-10 PC to Amiga keyboard adapter up on eBay right now. Once complete, you to plug in a AT (large 5 pin DIN) keyboard or small PS/2 mini-DIN connector on the input side and output could be a the DIN connector to the A3000. This is the bare motherboard so you would need to solder the wires on to get the keyboard connectors you wish. So, if you are handy with a soldering iron, you could consider it a kit project. I can send a wiring diagram if you want.
Have a look!
http://search.ebay.ca/_W0QQfgtpZ1QQfrppZ25QQsassZphatbaby77
