Malte, here is a partial answer:
1) We are working on a new upgrade/merge support mechanism for catalog files that will make committing catalog files from the translation server to CVS easier and less error prone. The new approach means we are doing the merging in OpenACS rather than relying on CVS to do it for us. If there are merge conflicts then manual inspection would probably still be required before we can commit the files to CVS. Also, I'm not sure I'd be comfortable committing a whole bunch of files to CVS without manual inspection.
3) It would certainly be fairly easy to generate tarballs with catalog files from the translation server. If you want to work on this feature, Malte, feel free. I can point you to the procs to use.
Thanks for the feedback!