Is there any way to make a community driven “Tribes” game?

I know the rights are owned by Hi-rex, but we already had Midair and I think something else tried to re-create it.

Is there any reason we can't make our own version now. Clearly Midair found some kind of way around it, does anyone know what parts of the game are copyrighted?

I've been working in the Ureal Engine since UE3 and I've often wanted to do it, even just for fun. I couldn't quite commit to a full solo dev version but I could definitely help out with the gameplay systems