Something close to this is already being worked on: Scan the source of gcc-2.7.2.x or gcc-2.8.0 for "bytecode".
I don't know if that's the same bytecode Java produces. Somebody knows?
No, this is not Java bytecode. It is a gcc bytecode that never made it to prime time.
Actually, it would be nice if a new target (backend) to Java bytecode was done, then all front ends would be able to compile to Java bytecode. Then, any lanugage front end could be used for making applets or other such stuff.