I've only seen the hacked-up M72 in 20th Century Weapons, but other than that, are there any http://en.wikipedia.org/wiki/RPG-7 mods out there?

Here, http://fallout3nexus.com/downloads/file.php?id=11887

You sir, are a gentleman and a scholar.

Does it animate properly?

No it reloads just like the missile launcher you drop the RPG in the top you dont slide it in the front, so its not perfect but I personaly can live with it. Another thing is I dont know where to get ammo for it but the xCALIBR Munitions shop sells RPGs that dont work for it so i just buy those and cheat to get the real thing. And on that note is it possible to change the ammo the wepon uses in FO3Edit?

You could open the geck and switch the ammo. I'm considering doing that if I download it.