To avoid melee misses the Hit Rating is 263, without buffs such as heroic presence. To avoid dodges Expertise is 26, with glyph 16.
In higher end gear both are achieved without gemming, enchants, food or potions. It is said (folklore, did not see an official confirmation) that in tank switching fights the taunt resistance of the bosses are lowered. In such fights pallies have three ways to taunt: Hand, RD and in worse case Hand of Protection on the other tank.