Although dated, the Garmin Zumo 550 is a very popular choice here in Australia. They are still available S/H but starting to become rare now.
I have one mounted on my XT660Z and it works well. However am considering upgrading to a Zumo 390LM with integrated TPMS (Tyre Pressure Monitoring).
Mine has City Navigator and Topo mapping installed....99% of the time City Navigator provides all the information I need.
Garmin Zumo GPS's come with mounting hardware.