Mike,
You can pair skeletons inside iAvatar and, although they will become a "new" generation they load OK. With an extra set of "arm" bones you can disable the skin to regular arm bones and enable the extra set. In the animation menu you will find means to transfer the left leg motion to the right new "arm-leg" and viceversa with the other set.
This is a technique I am working on as well. Can you shed more light on pairing skeletons?
"The enemy of art is the absence of limitations" - Orson Welles
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