Does anyone know for sure if the new Troll racial, Da Voodoo Shuffle, stacks with the talent Toughness or not?

Untalented Frostbolt Snare Base: 9s

Expected Durations:
Troll: 9s * 0.85 = 7.65s (7 rounded down)
Troll + Toughness (Additive): 9s * (0.55) = 4.95s (4 rounded down)
Troll + Toughness (Multiplicative): 9*(0.85)*0.7 = 5.355s (5 rounded down)
Troll + Toughness (Non-Stacking): 9 * 0.7 = 6.3 (6 rounded down)

Actual Initial Duration:
Troll: 7s (confirming that times are rounded down on the display)
Troll + Toughness: 5s

This observation matches what we saw for multiplicative stacking.

For kicks, I specced 3/3 Winter's Chill, which upped Frostbolt Duration to 12s.

Observation revealed: 7s

12 * 0.7 * 0.85 = 7.14s, so this rounds down to what we measured, confirming multiplicative stacking.

Thanks to Bryne for helping me test this with my mage on Beta.

On the topic of Tauren versus Orc shaman for PvP, if you knew what team bracket and composition you are going to aim at as your primary lineup, this would greatly help. For an offensive burn-based composition like Shadowplay (Resto Shaman, UA Haunt Warlock, Shadowpriest), I would pick Tauren for additional pressure and CC on your opposing team. Even at present in 70 I've seen War Stomp win games for Shadowplay compositions. If you aim at a more defensive lineup (or one where focus firing you might be an option), such as Double Healer with a single DPS (most often Paladin Warrior Shaman), I would go Orc. Even though their stun resistance is being reduced (I'm unsure of this), their racial on top of the stun resist will still help a lot on Double Healer 3v3 compositions. In 5v5, I would aim for Tauren hands down, especially if you run a JAC (Shadowpriest, Haunt Warlock, Mutilate Rogue, Frost [Or Arcane] Mage, Resto Shaman). As for 2v2, I'm not sure if Double DPS will even be viable in WoTLK, so I would go with Orc if your primary lineup is 2v2. However, if you're going for a general purpose PvP race and are unsure of which team compositions and brackets will be your first priority, I would go with Tauren. Simply because War Stomp provides utility in two [3v3 & 5v5] brackets as opposed to the Stun Resist racial only most likely being useful in one [2v2] bracket, although Blood Fury is still quite nice.