I've got a draft spec for 3.0 now, you can see it here. Comments welcome!
My goal is to take enough tanking talents that I can tank trash and boss adds, but optimize bear threat and cat DPS over bear survival. It's clear that the new feral tree requires a lot of choices at level 70, but since we have a warrior main tanking most bosses in our guild I'm going more for utility. So my logic was to take most of the core tanking talents Kalon recommends on his blog, but make some compromises for DPS. It may or may not work out, but I wanted to try something different.
Survival-wise, I'm missing Natural Reaction (6% dodge) and Protector of the Pack (12% damage reduction in bear form in a raid). DPS-wise, I'm missing Omen of Clarity and Improved Mangle. Also missing my beloved Nurturing Instinct. I used those points on Rend and Tear (more threat and DPS) and Infected Wounds (10% attack speed debuff! awesome utility if it stacks with Thunderclap on bosses.) Basically I'm going to be a somewhat fragile bear, but I should be able to put out a lot of threat and do a lot of DPS as a cat.