The McIntosh MX5000 looks like my old Sonomatic AM radio from my '63 Riviera, and the only deck I know that cosmetically integrates very well with older Buicks.
http://www.mbd-indo.com/Product/McIntosh/Mx5000/Mx5000.html
http://www.mbd-indo.com/Product/McIntosh/Mx5000/Mx5000.html