I have a mesh of a mech, which is considerably wider than a human. I've tried rigging the built-in biped skeleton to the mesh, but because the skeleton's body is so thin, the arm bones end up very far away from the mesh's arms. This isn't a problem when raising the arms forward and backward, but when they are raised to the side, the mech's arms go off the hinges because they are rotating about something so far away from them.

I can't seem to scale the biped to make it wide. I tried using the snapshot tool to copy the biped to a mesh, and then I was able to keep the IK of the bone system and move the individual bones about. The problem is, when you export it like this, the bones aren't exported as bones. I guess they get exported as meshes. Is there a way I can turn the skeleton back into a bones system after rearranging the bones? Or is there a way I can scale a biped on the X axis to widen it? When I try to scale the biped, nothing happens.

Well, I asked a friend who is familiar with 3DS and found out I have to put the biped in figure mode and then it is scalable.

I have a similar issue, I can scale fine, but I think I missed or forgot how to re-arrange locations like shoulder (hence also the upperarm,forearm,etc..)
Its making it terribly hard for me to get a perfect starting pose, I seem to recall doing this in the past... I tried affect object only after I had already init'ed physique.. hrmm maybe thats why everything went wrong...
I may have just answered my own question. Not sure tho.. will be back after trying affect object only before starting with physique.