you might try this one. first of all the reason for rigging the low-res polyObject instead of the subDVersion is all about performance issues. put the low res on a layer, put the subD-version of it onto another so you can turn visability on and of for both.
do not bind the subD to the skeleton. bind the low-res and use it like a lattice to influence the subD. in case you have a complete body, cut it into symetric pieces and bind them to the skeleton. to influence the subD with the lowPolyObject select 1 part of the lowPolyObject and shift-select the subD´s controlvertices wich are overlapped by the lowPolyObject, goto -> submenu Animation - Deform - Create Blendshape.
I think it is Create Blendshape, but am not 100% sure about cause I have no internet at home right now, so can´t prove it. but I hope you did get the idea of it. this way you can swap between low-res and subD any time. update time of smoothed versions is horror, so stick to lowest resolution geometry wich is bent to the joints.
everything starts and ends in the right place at the right time.