Is it currently possible? No. Would it be awesome? Yes.
I don't think it's a case of not being intended, it's just something that hasn't been done. If memory serves correctly, it took KDE a while to get it done.
And it's all fairly low-level stuff. It's not a simple bash script that's running
mvs in the background so I don't think it's going to be as easy to hack into as you might like.
You might want to find a GIO developer (assuming it's still GIO that handles these things) and shake them until you know why this isn't in there yet. Unfortunately, GIO developers are a stealthy and paranoid bunch. They know you're looking for them so you might have to file a bug against it on the Gnome bug tracker to lure one out.
But in seriousness, remember the devs don't work for you (unless, bizarrely they do work for you -- which would be a strange coincidence). If you do find one, try not to startle them by running up to them, shouting and waving your arms around. Just quietly ask if it's a planned feature and if there's anything you can do to help.