Does the Ballista have any planned modularity? Swapping out the back section for a medical, exploration, or cargo variant would make it a great general 'rover' and one that could be used with the Carrack.

At this time, no future variants are planned for production, although we've seen some fantastic community suggestions. The rover that comes with the Anvil Carrack is an RSI Ursa Rover, not a new Anvil Rover.