I've always had a hybrid feral spec. I spend about half my raid time DPSing and the other half tanking (unless we're low on healers, in which case I swap to my Resto spec).
Currently, my hybrid spec leans a little more to the DPS side:
Talent Calculator - World of Warcraft
My thinking behind the DPS-leaning is that Tanking has to be good enough to survive (meaning if you're over-geared/talented, you can't survive...more), but any advantage in DPS is a practical improvement by reducing the fight duration.
I'm considering swapping to this, though, for more tank survivability, since healers are having mana issues lately:
Talent Calculator - World of Warcraft
I dropped Blood in the Water and Stampede, and I also dropped as much Fury Swipes as I could, in order to add Master Shapeshifter and Perseverance.
My thinking is that 4% Crit in cat form from MS makes up for some of the DPS loss in FS and BitW. And the Spell Damage reduction from Perseverance makes my bear form more survivable.
So, I guess my question is, knowing I can't have it all, are there any better trade-offs I've missed? Any general comments?