Of course a dual channel system (mobile/sat) would be very attractive. I'm not sure how the sat service plans would work unless somehow the mobile app could upload the track data (when needed) via the sat data plan (inReach/Garmin) via a wireless connection. I would definitely be interested for the future North American Sailplane Grand Prix.
This start up is already working on a similar product:
https://www.v2track..com/