The following macro (posted by Troodi of Maelstrom on the US forums) can be spammed to expediate the turn-in process if you've got a lot of Sunfury Signets (this will also work with pretty much any repeatable turn-in quests). You still have to click the quest giver every time, but at least you don't have to keep moving your mouse around the screen back and forth :-p
/script SelectGossipAvailableQuest(1)
/script CompleteQuest()
/script GetQuestReward()
Just put that macro in your action bar and press it three times each time you click the quest giver.
Thanks to Troodi of Maelstrom for posting it in the first place.