I was talking to a salesman at Dakota Digital at the Hot Rod Power Tour at Indy. He said they have a GN in their shop and will be coming out with a gnx analog dash for it by the end of the year. If you need more info, here is their website, although it is not listed yet:
1984- 87 Buick Regal/ Grand National/ T-Type/ GNX Instrument System
1984- 87 Buick Regal/ Grand National/ T-Type/ GNX Instrument System