Let me preface this by saying I've played as various sorts of tanks for four years now.
Prot, Prot, Feral. Even a bit of DK. Tanking is what I do- I am one of nature's tanks. Therefore I view Mages- well, originally I viewed them as a bloody nuisance, and then when AOE threat (and all threat for that matter) became completely trivial I began to view them as just another DPS, albeit one that provided me with no useful buffs. But my guild lacks Mages, and has way too many tanks, so perhaps it's time for change.
Actually, just glancing over a few stickies has confirmed that the spec I had in mind was actually more or less the cookie cutter spec. Even got a nice stat weighting from the sticky in this forum, props to the people who wrote it. Only question I'm left with is:
->What do Arcane Mages use PoM on now, since they don't go anywhere deep enough for Pyroblast these days?