ATM the only tablet i'm aware of that works is the Galaxy tab active 2 or 3
Keith was talking about a rebuild to strip some of the parameters so it may work with earlier versions of android, which would put the Galaxy tab active back into the frame
That would potentially open the window for the Nexus 7 tablet too, but only the LTE version
The basics for a tablet to work are BT , , GPS, a cellular connection (UK ) and the required android system
Other than that any tablet should work - its the rugged & waterproof bit that are the hards bits ;)