[p3lim]

The 6th return from GetFriendshipReputationByID(id) gives you the standing name of an NPC.
Also, the colors for bars are green all the way, since you can't go neutral or below with them.

To see how it could be implemented, here is a link to framexml and my addon, oUF_Friendship:

https://github.com/p3lim/wow-ui-sour...Frame.lua#L171
https://github.com/p3lim/oUF_Friends...ndship.lua#L80

As for the ID used for this function, you can gather them into a table by using this:

for index = 1100, 1500 do
    if(GetFriendshipReputationByID(index)) then
        table[index] = true
    end
end