Internationalization of MU-plugins "globally"


I have installed plenty of multisite plugins and they work great. Thanks.
It is not finished for me, I need to support multiple languages. Apparently, there is no ready, po/pot files so I discovered to work with "makepot.php" of wordpress i18 tools. To work with that I need to define a directory location for "makepot.php" so it can scan files. Considering, most of the mu plugins does not have separate folders for themselves, they just lie in the mu-plugins folder, when I let "makepot.php" scan all plugins files I end up with a global pot file consist of all -to-be-internationalized- strings from all mu-plugins. Then I have translated part of it to see how it works. I have gone through a few plugins etc.
However I could not find out how to work with po/mo files.. where do I put that "global" po/mo files? How do I make them working across all mu-plugins.
Actually, I was also wondering if it is possible to have that kind of "global" mo file for everything: mu-plugins, regular-plugins, themes.
I am a PHP developer myself, so feel free to give any kind of technical suggestions.

Thanks in advance