I found this today. It looks like it's been in the works for awhile in early stages, but is starting to gain attention now. It's called OpenRW. An open source GTA3 engine. Really cool stuff, I like seeing open source engine re-implementations
GitHub
https://github.com/rwengine/openrw
Youtube dev videos https://www.youtube.com/watch?v=jwrgZLI ... IIw7hn-cAy
Dev images http://imgur.com/a/gPJag#0
Out of the many open source engine rewrites, I think that this can totally be ported to Dreamcast. Along with OpenMW (TES Morrowind) and Xash3D (GoldSRC / Half-Life). It'd take a crapton of work, but those would probably be the best possible games to port imo
Who knows, this could eventually work with Vice City and San Andreas. Since I think they all used the same engine, with minor engine improvements between each sequel