Speculating:
I don't think I've ever seen a 'mule drive' done with roller chain.
It's damn hard on v-belts, so I wouldn't expect long life.
However, I think I've seen drawings of roller chain with twisted links, so the chain could flex in two planes. Never seen it in real life, but ISTR some of Berg's variants on cable chain having the right symmetry to do it, as of course does common 'bead chain'.
Mike Halloran
Pembroke Pines, FL, USA