If you're out of luck and low on time there are some options that have that dirty spirit on them that will still be an upgrade to what you already have. Cloak of the Dryads at honored rep with Guardians of Hyjal comes to mind. Hey you can reforge half that spirit right?
Please don't smite me for recommending something with spirit on it Archmage pants!

There are lists out there, but Siamat in Tol'Vir drops a nice Mastery Trinket that boosts spellpower when a mob falls below 35% health.

I saw there were a couple as boss drops but as Christian said it can be a massive pita getting a specific drop. I'm looking for more quest rewards. I guess Blizz does always like making trinkets hard to get.

I wish DPS casters would realize that you don't need spirit anymore.

TWICE while levelling, I've been beaten by DPS casters for a piece with spirit on it.

@cyanea

Most dps casters (except mages) use spirit. They tend to have talents converting spirit to hit. So get used to most dps casters (except mages) taking it gear with spirit.

Stonemother's Kiss http://www.wowhead.com/item=61411 from Deepholm is a very strong quest reward trinket due to the value of Intellect to mages, even if it's green.

At least Alliance has the World-Queller Focus http://www.wowhead.com/item=63842 from Twilight Highlands, I'm not sure if there's a Horde equivalent though.

Talisman of Sinister Order http://www.wowhead.com/item=65804 from Uldum is also a nice one with loads of Intellect and a Mastery proc.

@cyanea85
I would never roll against a healer for a healer piece. I'm referring more to quest and rep rewards. I think spriests might get something out of spirit though?