Is it possible to "stroke" a path (not a shape)?

Hello,

I have Illustrator 16.0.4 on a Mac 10.6.8.

What I want to achieve is have a stroke (effect or appearance?) on an open path. And keep that path editable (not convert it to a shape). Below is and example of what I'm trying to do:

On the left I have a path (with rounded ends) that I have used the Width Tool on. I want it to stay a path, but have a black "stroke" surrounding it. I've tried Stylize>Drop shadow with a hard edge, but it is always off-set. I've tried Stylize>Outer Glow (set to black color and normal blend mode) but always get a soft edge. I have tried adding a second stroke to this path in the Appearance Panel and making it larger, but it does not look right. Is there someway of adding the appearance of a stroke but keep the "shape" as a path?

(I'm more familiar with Photoshop; the way I would do it there would be Layer>Layer Style>Stroke)

Thanks,

Charles