Approaches to fade in/out objects

[hatsumatsu]

I'm wondering if anyone of you knows of alternative approaches to fading in/out objects (meshes, groups, ...)?

The recommended approach seems to be animating the opacity of materials to achieve a fade, but in case of complex objects with multiple meshes and materials this can look odd since overlapping meshes become visible.

Do you think it could be possible to build f.e. a shader-based HOC using stencils / masks / ... to fade the complete object?
Kind of stunned that there is little stuff out there for this very common use case.