Just still curious if this is possible?
That looks perfect for the array command ... notice how the intersection of the cross lines and the curve stays the same distance apart? Notice how the outside ends of the cross lines grow further apart and the inside end closer? Exactly what array does.
Try it, see if it works for you. The Lisp idea (as per ronjonp's code) is for keeping a minimum constant size at both ends, the array idea simply ignores this and only keeps it constant at the path itself. You can always add a 2nd polyline for your path, place it on a non-plot layer if you wish.
