maybe they should just make a forum sticky on how to properly implement new stuff...
adding to levelled lists via an ending quest script proofed to be totally great for me in fallout, you dont conflict with other mods that mod the same levelled list (unless theyre loaded after yours and dont use that method but just ignorantly replace that levelled list with theirs), the items becomes a natural part of the world and you can play with the trolls who ask like every second comment where the chest with your new item is

but there are soooo many ways...
make a shrine that requires offerings
give it to some hardass boss type enemy
have the player solve riddles
add it to npcs
let the player craft it
creating a new merchant who sells all your stuff has become quite easy too since NV id say...
and so on...
putting it in a chest btw is somin we can even do without a CS/GECK... just needs a hex editor (see the very first fallout 3 mods)