Weighted Pose Animations without Blending

I have a facial model exported from a 3D modelling package with several animation poses (smile, open, pucker, blink, etc.). I need to be able to combine these poses with weights and without any Unity blending from frame to frame. The weights don’t have to add to one. For example, I might have a weight of .5 for ‘open’ and .75 for ‘blink’. Each pose animation consists of 5 identical frames with bones rotated and/or translated to give that pose. I need to be able to change the weights on a frame by frame basis without Unity “helping” smooth things out. I’ve tried using layers, but with a fixed set of weights, I still get

Failing an easy way to do this, is there a way to get at the guts of an animation (bone rotations, translations, etc.) and create a new animation on the fly with my own calculated values?

Thanks for any insight you can provide!

Bones are just transforms in the hierarchy you can modify however you want.

Its also possible to change the weights, the Mesh class as well as other relevant aspects on the renderer give you full access to whatever you need to use it.
Generally unity does not smooth things out, it interpolates stuff over its define amount of time. So if something is too smooth / long I would check the timing