I see a few wall mount (not in-wall mount) Jukes but I never get to see just how they're mounted.

I was thinking of using a plate so I can (more or less) center the box along the wall rather than strictly depending on the position of the stud(s).
In other words I'm trying to work out how to use a back plate for attaching to a stud(s) without necessarily having the plate be dead center on the stud centers and then mounting the box to the plate itself. I would like to do this to avoid having to drill new holes in the back of the box when the box is inevitably moved when the wife gets that "let's move the furniture" bull.
I was thinking about using three L brackets (top and sides) which would be mated to an appropriately shaped plate. Mount the plate on the wall nice, square and level then slip the box w/brackets onto the plate and screw the brackets into place. Seems kind of tedious, but it seems like it would work nicely. Any ideas on this?