There's only one Ammunition NPC on Eldeon.
I think it's a disadvantage that the classes who use Ammo have to run back/tele 5 maps deep to get ammo, while all classes can repair in any map from the Hammers being added.
So far I've noticed an Ammunition NPC Should be Added to:
Shady Jungle Villiage
Smith in Sikuku Ruins.
These are two pivotal locations in game play. Shady is around the "center of all map locations on Eldeon, and the Sikuku Ruins Map is the ending map.
There's not a huge problem on Luna, as you can Scroll to Eucar, then use the portal to get back to your map quickly.
I'm sure some location could be Added to Oro as well.