I made a texture to make it more pleasant for the eye while I’m working on rigging part. 

OK, I set up a biped inside the character mesh and then I applied physique modifier.
One thing that I noticed first was that when I switched to vertex sub-object I experienced
a lot performance decrease. (poor 8800 GT is possibly the reason. my CPU is fast enough. core i5 + 4G of RAM). So I decided to tear up the mesh (body, arms, feet, head, … ) and apply an instanced physique for all the parts. So I could hide and unhide the unnecessary parts to increase the performance. I don’t know whether this is a standard pipeline or not and if I’m gonna face difficulties as the work goes forward? I need your advice on this.
The kind of behavior I’m looking for this armored body is rigid movements unlike soft human or animal flesh… . So I used the rigid type for all the envelopes. and then I adjusted the envelopes of the upper body and in vertex sub-object I defined precisely weights of vertics for each deformation spline. I tried different combinations and weights and none of them were satisfying. Here is a video which demonstrate the problem:
[vimeo]17880877[/vimeo]
separately in another scene I also set up a few master/slave relationships in reaction manager dialog for shoulder pads. This is exactly the kind of rigging I’ve considered for this character. I know that I can combine a biped with external hierarchies. but I don’t know how to bring this feature into my biped. is it possible?
Here is the video with master/slave relationships:
[vimeo]17880897[/vimeo]
Note: I also uploaded the biped scene. download it from HERE .
your POVs are kindly requested and highly welcome.