Hi there,
I have spent the morning fiddling with the exact same problem actually, just wanted to tackle it to see how easy it would be, but I think I have managed to solve it to some degree.
I have attached a modified version of SkeletonComponent.cs which creates an array of GameObjects, as well as an array of BoxColliders which are then attached to the GameObjects. The GameObjects are named the same as the Slots and added as children of the main animations GameObject. It is coded so that (fingers crossed) it should place a GameObject in the center of each Quad, attach a Box Collider to said GameObject and finally re-position, rotate and scale the GameObject/BoxCollider to match the Quads dimensions each frame.
Unfortunately the BoxColliders in Unity do not support skewed aspect ratio's mentioned above as you can't specify the BoxCollider corners, you can only specify it's center and x/y scale (a real pain in the ass). This made it a little bit more tricky to code up but I think this first solution is a good start. I don't know what the overhead associated with moving so many different GameObjects + Colliders + RigidBodies (required for non static colliders in Unity) actually is, but it shouldn't be very difficult to take the script and modify it to only create and update GO/Colliders for the quads you care about.
I marked all of the bits I added in the code, it should be easy to see where they are.
Hopefully this helps someone else out, or maybe even Nate in terms of getting to grips with how native Unity Colliders might be incorperated in the Unity runtime. I hope I used the correct multipliers (bone scale, rotation, etc) throughout but can't be sure, maybe someone can point me in the right direction if not. All in all it seems to be working though.
Cheers,
Robert
Edit : Here's a picture of it working