Prelimniary investigations reveal that it should not be -too- difficult to use a skinned-mesh-renderer for animation of fuel lines and engine-bell setups. This should eliminate several of the model constraints that are in use for each model, while cleaning up the fuel-line mesh geometry.

Hmm.. apparently skinned-mesh-renderers are -bad- for performance, and should -really- only be used where mandatory (organic characters):
http://forum.unity3d.com/threads/skinned-meshes-performance-issues.261492/
Will continue investigating.

My current method of fuel-line deformation -works-, and is fine for me from a visual and performance perspective; so perhaps I do not need to swap over to using SMRs.