I've got an aftermarket speedo/tach unit on my bike (1980 GL1100). It's a Motogadget Chrono Classic (link to motogadget.com
). It has analog display of the RPM and speed is shown in the first line of the display. The second line of the display can show a number of different things, cycled through with a menu button.
RPM input is a wire connected to the ignition coils and speed input is a mangetic sensor at the wheel. It has LED lights for oil pressure, neutral switch, turn signal and high beam. It can also display oil pressure, oil temperature and water temperature, if you have the right sensors wired to it.
I think it's a nice unit and replaces all of the original cluster except fuel tank indication (I just drive a certain distance between fill up or until reserve tank).