Now it seems you use the GPS output to allow the compass repeater to display speed. Great idea! But I still want the compass repeater to be able to display distance as well (like the TripMaster XL). Can you use that GPS output data to calculate distance (speed/time=distance), and allow that to be displayed? This way if the TripMaster has a broken sensor, is calibrated wrong, or otherwise damaged, you can switch to the compass repeater to display distance as a backup. You will need to provide a connector so the handlebar switches can be connected to the repeater when a problem is discovered, but that's better than trying to navigate with no odometer.
Or, better yet, add the GPS connector to the Tripmaster so it can do all the odometer functions AND do the compass repeater function too!
I suppose you don't have available I/O pins on the processor, but I can keep dreaming that you'll find a way to do this.