Quote - I can handle shoulder and collar bends, using something I've called an internal IK chain with parented endpoints, but that won't work over an  IK chain of 50 bones long (the amount of links in the longest chain).

Times ago I did something with IK-chains for a very long chain. At the end, I used 4 or five parented parts of chains managed with a Python script. Maybe this will work here too.

Quote -
Another option would be to make them rigid decorated groups tied to an invisible strip of dynamic cloth.

Yes, I used this option before and it worked perfectly. Mutch easier as to deal with IK-chains, especially because heavy use of IK will need a lot of resources.

Really nice model, by the way.

---