"Poltergeist Shield" MTX from Tormentor Supporter Pack should be applicable to quivers.

This particular shield MTX can work very well in ways that no others can.

1. There aren't any MTX for a quiver slot that do not overlap the back attachment slot, to my knowledge. Sort of lands you on "If you want to use one of the MTX you paid for in this slot, you cannot use one of the MTX you paid for in that slot."

2. There are quivers with block mods. You can block while using a bow/quiver setup. You can also have 0 block with a shield. The MTX doesn't *require* you to actually block anything, and the animation it provides does not involve your character.

3. The MTX doesn't "apply" to the "offhand" area of your character - visually anyway (not talking about the other side of things.) so it's not like it'd be "attached to nothing" - the MTX is basically an aura effect with a trigger-on-block animation that's attached to a different MTX slot on the paper doll.

4. It would be cool as heck. You could even go and make it so it has an alternate animation specifically for being equipped on a quiver - instead of blocking a blow with the rocks, it could toss one every time you shot a projectile.

The end.