Oh, no it's not based on any other mod. I wasn't even aware one like this existed, not that I went looking or anything. I just thought of this earlier today and thought I'd like to see it in game, then posted it here in case anyone else might get a kick out of it.
And I decreased the power of the grenade since it seemed like it is a little safer to use as a grenade, since you don't have to worry about hitting something directly in front of you, or shooting a nearby teammate in the back. Plus you can carry a primary weapon and throw grenades with a lot less hassle than carrying a primary weapon and a small launcher.
EDIT: Oh and thanks for the translation, I'll be sure to add that in.