Custom Gizmo Shapes

I've been increasingly using Gizmos in my Geometry node projects, and I have been increasingly wondering if there could be a means to implement some kind of custom shape system, similar to how we can do with bones. Either create a mesh outline shape outside of the editor or within the node tree itself, then assign that to be the gizmo shape.

The linear gizmo already affords us the option to pick between an arrow, a box or a cross gizmo, so I'm just suggesting we also add an option for a custom shape, as well as offering that option for the Dial and Transform gizmos.