Shield master?

[Sirrocco]

It occurs to me that the sun paladin has a tree that adds an automatic shield bash on to your bump attack in its first skill. Stone Wardens *also* have a tree that adds an automatic shield bash on to your bump attack in its first skill (while also improving the overall damage of shield attacks). Would the two stack?
Beyond that, being able to grab shield expertise from the bulwark to crank up the effectiveness of whatever shield attack tree you chose (probably old-fashioned Shield Offense, so as to finally enjoy riposte while using the dual-shield thing from Stoneshield)

Too bad you can't TK a shield.

[breadsmith]

I ran a character that was basically this. It was a while ago, but I think they stacked.