This sounds interesting, I'd like to hear the answer.
When I build freshwater moss walls, we use netting - but obv that wouldn't be practical for coral.
At my LFS, they use plastic Egg Crating, and epoxy a layer of liverock bits onto it, then patch the corals on in the normal way.
I hope that helps a bit, I'm not a salter.

Might be worth poking Atnixon, Kev or PerfectBlue.