the Ubuntu po-file database is ~2.6GB, then converted to mo-files and leaving out some which could not be converted results in ~800MB. Of that you do not need some too exotic locales -> ~ 500MB, on average may be 15MB per locale. With addlocale 1.6 I had ~60% of these mo-files per locale in PCLOS. Now I found a trick to have ~95% of them in PCLOS and the remaining mo-files are Ubuntu specific, so not relevant for PCLOS. Still there are very few which need to be imported from somewhere else, but 95% of the users will not even need them. Addlocale 1.7 is progressing nicely and many more applications will be converted, but it will take some more days to finish this. And with 98% conversion it will make the mo-database superfluous
Tomorrow, when I am back at work, I can attach the script to generate the mo-file database, so you can look into this and see what is useful for you. Remember that this database is based on Ubuntu. Obviously, this database is not complete and you will still have to search for some mo-files in other distros, but this is really striving for perfection. Addlocale 1.7 will give you at least 95% of what can be achieved, which should be fine for almost anyone.