First time posting, hoping to contribute something. I have searched many weapon leveling skill posts in order to find something similar. However, I have yet to find someone who points out this quest in such a fashion.
I've found a means to level your weapon skill on a particular quest. That quest is: Hell Hath a Fury - Quest - World of Warcraft.
Normally, these quest npc's are killed after applying a debuff and dpsing them down. However, if the quest NPC is stunned when death occurs the game does not follow through with the planned event. Instead these NPC's become stuck at 1 health and as such can be attacked infinitely provided the DPS has some means to replenish health.
In this instance, my rogue had kidney shot the NPC before it died in order to bug out the death event. Making it stick at 1 hp.
This particular method of leveling weapon skills could be very useful for an individual who has not yet done this quest and has managed to hit level 80. This is because the quest NPC's are only level 77 and produce very low dps. Something which most classes have an easy time overcoming. Keep in mind that you may bring a friend along if they are along the same phase stage as you with that particular quest. The questline starts with Spirit of Rhunok - Quest - World of Warcraft.
I understand that this strat / exploit will not work for all, but I hope it will help at least someone. Also, please let me know if this is a repost - like I mentioned earlier I couldn't find a similar post. I will however delete this if it is true.