So... each of these projects will have it's own translation file, and All I'll have to do would be to add their translation dirs in app config, or within an included module, right?
Okay, going further from this point,
Is there some simple way to add translations from included module in an app, but still preserving different domain? Most preferable by extracting it's translations to own translation domain by running python setup.py extract_messages (and the other commands). I'm going to add some possibility to modify all translations from within app, and it seems that the best way to do that is to keep them in the same place.