I just wrote a plugin based on the build in Hatch Outline filter. It adds the ability to go from thick to thin strokes using the Offset Path option.
The slider sets how much it should expand the shape before the filter ultimately intersects with the original shape, this is to avoid jagged edges from the hatches, or you could set it to zero if you like the jagged edges.
I’ve made a fork and pull request today, hopefully it might be usable as a small little effect for decorative typefaces.