Funnily enough, I was asked yesterday about something similar.
We've got a choir on stage, with a conductor standing on a small riser on the auditorium floor. The band surround the conductor on the floor, choir and soloists are on the stage which is approx 4ft high.
The problem is that the choir can't all see the conductor, only the first few rows. One potential solution is to add risers for the choir, but that'll involve quite a lot of hardware and expense for a show that's already tight for budget.
Raising the conductor might help, too, but much higher and they'll block sightlines for the audience.
Some video relay seems like the obvious option, but they've experimented with modern digital kit without success - there's just too much latency.
I've been asked about possibilities. I know composite / analog is the way to go. I'm not sure though if, for example, running a composite signal into a modern flatscreen TV will still be latency-free, or if there's inherent processing / upscaling involved. The choir are large enough that we'd need some decent sized screens and alas my 32" CRTs went into a skip some years ago...