I've been trying to create a cantilevered line that is affected by gravity, but is fixed in its beginning part of the line (pretty much like a flexible rod or HAIR).
Have you looked at the examples in the 'bending' folder of the kangaroo examples? There is one that does exactly what you describe, simulating the behaviour of an elastic rod.
Stupid solution here, didn't read in time Daniel's comment :P
You could subdivide the wanted line in segments, and use align force component between each element and its successive (with shift list, not wrapped). Anchor end points of first segment to fix "hair bulb" direction.