Has some one tried to add a Bluetooth unit to the USB port.
Then read from an external unit (for example smartphones) read the GPS coordinates for geo taging ?
I have a 50 D body.
Another, less complicated solution, you might consider is using an app like GeoTag Photos (https://www.geotagphotos.net/). It is an app that runs on your phone to keep track of where you are and a desktop app that will geotag the photos you took based upon your location at the time. It has worked well for me and seems to be a better way to achieve what you are after, unless I misunderstood.