Could something like Microsoft's Expression live vector brush effects be created for Inkscape's LPE?

If you have not seen what it does, Expression allows you to create a path and stroke the path using another object where the width of the stroke along the path is based on an contour path (think XY chart) where the width (X) is the location along the path to be stroked and the height (Y) is the width of the stroke at the point along the path. Ideally, the stroke object could be made up of multiple paths with various characteristics. For instance, you could create a stroke object that mimics a water color brush stroke.

- Tony