I've been looking into it and decent (fov + crosshairs minimum, maybe everything but I'm not sure yet) widescreen support doesn't seem too difficult to mod in.

I don't really know how it works with servers though, it would modify the cgame vm/dll file, does that mean it would only be able to be used by mods/locally or if it got added to ioQ3 server files or whatever would it be available for everybody?