I actually really like the idea of a shaman tank build, but with parry and grounding totem being min level 30, it is agonizing for me to think of staying at 29 with this build idea, haha.
To your question, though--I've only farmed Emissary cuffs once and got Stamina in the process, while looking for something else. What I actually wanted took about 3-4 months, maybe five or six hundred runs, and that was with a level 80 hunter bombing through the place in minutes and running me to the boss with pack. To me, they're really just not good enough to justify the grind when you're gaining 3 stamina (if you get lucky enough to find +9 instead of +8) and giving up 4 Spirit and 4 Agility from a dirt-cheap pair of Barbaric Bracers.
In my experience, even though our brains find it more pleasing to min-max on a single stat as much as possible, when you're sacrificing 8 useful stats for 3, you're probably not being optimal, even as a tank.
4 Agility is 8 Armor, 0.2% dodge & crit. Spirit is mp5 after 5 seconds of not casting, which will happen a decent amount as a tank, especially if you have a healer, so you can save mana for low-rank shocks and totems for utility. You can argue that 30 extra health is still better in some situations, but you have to admit that it's also worse in a lot of others.