Please add the User Arrow option to the list of arrows available for leaders in Civil 3D styles > Dragged State tab similar to what is currently available in AutoCAD dimstyles.

Adding the ability to use user defined arrows will allow for possibilities such as those described in this blog post by Jaiprakash Pandeyo.
http://www.thesourcecad.com/how-to-make-custom-arrow-style-in-autocad/