Hi Faerygirl,
I'm trying out a Dracula vampira on a terracotta tile with the bottom sitting in a container of water. So far so good- just keep having to spray the darn aphids!
I also have a Stelis porschiana growing mounted on a treefern which the grower said he grows sitting in a tray of water, in fact the bottom of it had algae on it! He lets it dry out some in Winter. I've put it sitting in a tray of water and it has grown and rebloomed for me, so I'd say why not give it a go?!
Damian.