Is Character Limb Dismemberment Possible?

I found a script i the asset store: Piecemaker Mesh Destruction, I didn't try it, but it could be possibly what you are looking for.

The easy way: Your character should already be a 'sleeping ragdoll' - complete with rigidbodies and motion-tracking (so your code knows how fast each rb is moving/rotating). When it gets chopped up, enable all the rigidbodies and disable animation and it'll fall like it should.

For each piece you want to cut off, create a prefab at the bone's location & rotation, then scale the bone to zero relative to its parent (.localScale = Vector3.zero) and move it directly to its parent (.position = parent.position). Give the prefab the velocity you've been tracking and it looks pretty reasonable.

The hard way: It's finally possible to slice skinned meshes (see SkinnedMeshRenderer.BakeMesh in the script reference): here's my one-day test. With only ~4700 vertices, it's a several-second pause to do the cut, but coroutines could potentially hide that.

You can use existing asset to do it: https://www.assetstore.unity3d.com/#!/content/102813 Screenshot: