Quote Originally Posted by ss-kalm View Post
More playing and investigating:

If you add a bevel to a single line (start with external bevel so you can see what your doing) , change light elevation to 90 and add a linear gradient you can adjust the bevel internally to fill the line. The line still exhibits all the properties of a line and can still be shaped with the shape editor.

Have included the .xar for anyone interested.

See original thread here