First off, I would like to know exactly what the Dreamcast is capable of in terms of using an open source engine. Can the code for the engine use an OpenGL or Direct3D rendering? Does the original code have to be written for any particular OS like Win95/98 etc? What can the SH-4 actually do with a game engine that was originally coded for a Windows OS and why can't it be more efficient?
I've seen on these forums that Quake runs only in 8bit texture mode which is terrible considering it's pallette wasn't very deep to begin with. Has anyone considered any other open source game engines? Irrlicht is a fantastic looking game engine and you can find all the info you want to know about it here.
Another very attractive looking game engine is the Cube
engine. I'm not sure, but I thought it was based on the Quake source code...I may be wrong. Finally, Garage Games
can license an engine for very little compared to other 3D licensed engines. This might be worth something to a developer who could potentially market a game for the Dreamcast in the same fasion as Feet of Fury or Inhabitants.
I guess it would be best to know exactly what the DC is capable of and then work within those limitations.