I don't think a C&D would be too much of an issue. The New Era
mod for Half Life 2 hasn't had any problems, and one of their mod members has even been to the LucasArts studio and told them about it and they said it was fine.
However this has been proposed a couple
in the past, and they (the coders) agreed it would be too much work to rebuild the engine which we don't have.