I relocated the dash gauge on my XSR900 that left some exposed bolt holes. I used them to mount this dash panel to that has room for a small momentary on switch (8mm in diameter, secured with a 10mm hex nut) that is wired to a garage door opener and a USB outlet. 

I don't have the details of the USB outlet any more but the hole for it measures 21.7mm x 15.5mm. A similar one to what I originally purchased is pictured.

The cover for the button and the USB cover need to be printed in a flexible material.