Light rope/chain, heavy ball?

Been trying to make a light chain with a heavy ball attached using configurable joints, but it's very unstable.

The docs say at most you should only have the mass difference between joint-connected rigidbodies be about 2:1, so does that completely rule out the possibility of what I'm trying to do?

Or is there another technique I can use?

I need the chain to respond to collisions with things as well, so the single joint/particle visuals trick won't work here.

 

the problem here is you need a lot of iterations to resolve it without stretching, and a higher physics rate - or a new kind of joint (ie custom joint) for each chain link.

 

Hmm yeah I'd like to keep the computations to a minimum. What do you mean custom joint? Do you mean write my own implementation of a joint concept in script, and handle it all in there? Or is there some kind of built-in way to come up with new joints within the confines of the physics system?