No guarantees on this but I'm currently petitioning Hi-Rez Studios to release the source code for the original Tribes game. They released the game as freeware back in 2015 so it's not a huge stretch. I even have the game's lead designer, Scott Youngblood, on board. He actually has the source code but would need permission from the IP holder (Hi-Rez), to release it.
For those of you who are unfamiliar with the game, it's an online multiplayer first-person shooter that was released for PC back in 1998. You can see some gameplay in the video below. I'm sure it would be a perfect candidate for a Dreamcast port. Scott is a fan of the Dreamcast as well and agreed it would have been a great platform for it.
Just picture this: The source code is released, and the game is ported to Dreamcast and a bunch of other platforms with cross-play between all of them. This could be huge!
If you happen to be on Twitter, feel free to retweet this and help get some momentum going. Hopefully Hi-Rez will notice.