So, you're looking for a USB socket that fits into a pre-existing hole on your RT's dash? Sounds like a good idea. I have a usb plug mounted on my GS in an out of the way/non-obtrusuve/accessible place, but it is rectangular. It has a rain cover, but the plug is always occupied by my Rube Goldberg bluetooth setup, also unobtrusive. The sleek covered style of the RT would preclude that though. It would work for a roadster, but likely not an RT, unless there are nooks or crannies to hide one.
Or you could drill a hole in your dash and mount this or something like it
That could probably be done easily and look pretty neat, I think, and address your concerns.
Fo my riding, and YMMV of course, I charge everything up overnight, so I do not have to charge on the road. I am able to do so, if need be, via my above USB port, or through the accessory socket, but in usual riding, even long distance/long day things stay charged so adverse esthetics you describe do not arise.
another option is to run the port to the topcase for charging on the go, but realtime while-riding access would be problematic. Still you could charge stuff back there, out of sight while underway.
If you figure out a way please post.