Simple Mod Request - An open hand

[Threeshades]

Basically all im looking for is an item that forces versatile weapons to be wielded in one hand by occupying the other. Some classes can get the duelling style but have no shield proficiency so they can't use it with versatile weapons (such as my Blades bard).

I imagine that would be very easily achievable by making what is effectively a shield item that doesn't have a visible model, add AC, or anything else and that every class is proficient with.