Most Amiga users back in the day did NOT like this keyboard and there were several adapters from various companies that offered the reverse of what you and I would like to do: hook a 2000/3000/4000 keyboard to the A1000. I have never seen an adapter that allows the use of the beloved A1000 keyboard on any of the other Amiga systems :-(
Perhaps Redmond cable could make one? I'm e-mailing them right now to see about this. You in? Maybe we could get the price down with a quantity order.