Sure, use
MMkeyboard from Aminet which adapts the PC keyboard protocol to the Amiga keyboard protocol.
It's then just a matter of removing the A600's key matrix to serial converter (a Motorola 68HC705 MPU) and connecting the serial clock and data lines.
Simple enough to do, plus there's a heap of keyboard modification notes on Aminet if you need some detail. Most of them are for the A1200, but the A600 keyboard operation is essentially the same.
If you were more thinking of off the shelf stuff, not sure what's about these days. Check out the likes of
AmigaKit and
Velisa.
