I am unable to verify that the One handed and Weapon and Shield Styles stack.

 

The combat log does not show it, and the character sheet does not show it.

 

Has anyone seen evidence of these two talents stacking?

They do, but you have to watch the combat log like a hawk to witness the graze-to-hit conversion

For added fun you can make a Fighter with a 3 Perception that will hit almost all the time.

 

Use a Flail, Confident Aim, one handed style, the Paladin accuracy aura . You'll have like 30+20+15+30 an 95% graze to hit conversion.

But that does nothing for you if you miss.