I think it's really great that SC2 is available for other OS now, also with the ScummVM you can play a lot of old games without having troubles in Windows or Linux.
But how about making this with other great games? Like Wacky Wheels or Super Kart? I read somewhere that the programmer posted a part of the sourcecode but unfortunately just a small part. Would be really great if you can make games like these for Windows nowadays and with network playing!
I'm not familiar with Super Kart, but I've actually been approached once before with a request to remake Wacky Wheels. The major problem here is that the source code is not available (apart from small simplified snippets like in this discussion on GameDev about programming graphics for Wacky Wheels-like games and a short snippet for Dopefish handling. Furthermore, Apogee/3D Realms still seems to think they can sell the game, which means that most of us are stuck with the shareware data files.
The interesting parts of the game code from a remake point of view are the gameplay code and the game data handling; most of the low-level graphics, sound and input code will have to be rewritten anyway (and Wacky Wheels would be a natural for 3D acceleration using e.g. OpenGL). Complete source code makes this sort of thing a lot easier, as you don't have to spend a lot of time figuring out what's going on, you just read the source (although heavily optimised 3D code in assembler may be quite hard to read, it's still a lot better than machine code).