Advanced Push modifier

[DoonBarrum]

This is allerady possible by using CAT muscles:

MusclePreview

Use a skin wrap to apply it to your mesh.

I don't see how that can achieve the same result? Once skin wrapped the vertex data is set and it applies to the initial setup. You are unable to f.example drag a muscle through a tube and have it push in multiple places, it will only drag vertexes from its original position. 
Also, you are unable to select any object, if the push modifer would support any selected object as the push normals you could basically drag a teapot through a tube and have the tube conforming the teapot.