Have been asking for multiple years. Hasn't happened. The closest is the custom toolbar which is not as handy and has it's own set of limitations.
As a note, when we started we were by the salesperson that you could do custom shortcut keys. After the purchase I couldn't figure it out so I finally got in touch with a tech that was assisting with initial questions and was told that function was not present.
I doubt it will be added as PTC has indicated they're focusing on Illustrate by introducing more 2D functions and the eventuality that Illustrate will replace IsoDraw. Don't know timing, but that would seem to indicate that new features will be limited to high payback.
BTW, we're on 7.3, M031 and custom shortcut keys are no where to be found.