A couple of questions

[AnonYMouse]

I appreciate that you want the "look" (that Bulbo isn't spherical, but hanging some rhizomes). Lets work this out in reverse.

What plants grow in mounds?

some Bulbos
Dendrochillums
Oncidiums
Masdevallias
Gongora
Stanhopea
etc.

And instead of a branch, deconstruct a wooden basket and reassemble into a raft (remove a level or two of height). Or pot up in other types of baskets. Or mount on a tree fern pot or ball. People were getting pretty creative with Hygrolon and the horticultural scotch pads (I can't remember what they were called).

Now, mix and match the growth characteristics (sprawling rhizome, shallow roots, etc) with the properties of the "mount".

And not least of all, you'll need patience, lots of patience. That bulbo in the pic didn't happen overnight or even over months but years.