Combining the sd card solution with a backup program is a great idea -- I had subconsciously thought that a backup program might not have been compatible. But I don't know why I thought that.
The whole thing could be much more useful now, as the external card both provides a backup solution and finally a way to get data out (and improved data-in too). I'm tempted to re-install GVM again, but maybe there's a new version coming out soon (isn't the time-limit for the current version this May?)