Barb Fast Movement requires medium or lighter armor, so any mithral full plate would work. But you'd need heavy armor proficiency (feat or multiclass with Fighter, Cavalier, or Paladin) in order to not take the massive armor check penalty on your attack roll. In PF, mithral makes armor lighter, but you still need to be proficient with its original weight category.
The only Totems I like are Spirit and Animal. Latter is nice for pounce at 10 and the natural armor is decent, too. The lesser one for claws is pretty sucky, though. Don't go TWF, pounce is still decent for 2H weapons, not as helpful as for TWF, but far from worthless.
Spirit is cool if you have decent cha due to a demoralizer build. The concealment from non-adjacent attacks is awesome for screwing with big monsters.
A lot of people like Dragon, but it's SOOOO costly and IMO the first two totem powers suck mightily. Only the greater dragon totem for flight is any good, and I think you're better off just getting winged boots, which you can easily afford by then. So yeah, I do not recommend dragon totem.
Don't take Sunder, if you don't want to destroy treasure, it's only a minor debuff that you wasted a bunch of attacks you could've been doing hp damage to achieve. Along with the 3E issue of "a lot of monsters don't use items." Trip is likely out of reach, ou need int 13 and combat expertise. Dodge is decent, note it buffs CMD also. Toughness certainly doesn't suck, but it's definitely less exciting...
Raging Vitality is basically a feat tax so rage won't inevitably auto kill you somewhere down the line because Paizo decided to regress on the progress of 3.0-->3.5 *sigh*, you may want that.
If it's an option, I think Cornugon Smash is the next best barb feat you can take after Power Attack (and it requires PA anyway). Look that one up on d20pfsrd.
I have no idea why a 2nd level of Lame Oracle would boost your speed, you lost me there.
Far as staying in Barb...Invulnerable Rager's DR is IMO the only reason to really stay past
level12! I mean, what else do you really get? All the Rage Powers after that point (Come and Get Me) are garbage... Will boost at 14 is ok, maybe stick around just for that... The capstone at 20 is pathetic compared to almost every other capstone, and you can get fatigue immunity LONG before Tireless Rage. And...that's it, no other barb class features at all. Other than improving DR for Invulnerable Rager, seems kinda silly to stay in Barb after that.
EDIT: Systole, when you get to Totems, you may want to address this unanswered issue:
http://paizo.com/paizo/messageboard...ypeFromAPGAllowABarbarianToTakeMultipleTotems