As long as we can wear 2 armors (one over the other) at a time, i think it is possible. The armor below should be transparent (no texture), when you are hit, that section of the transparent armor "moves" up and "voila", your limb is gone. Yeah, i know is not that easy but it could be a start.
Maybe it could be done just for head chops, you wear 2 helmets (the one below got no texture) when are you hit in the neck, we change the upper helmet texture to the no-texture helmet so it seems that your head is gone. Somewhere i saw a crpg video of guy dueling with no head so i think it might be possible.