Highlighting whitespace at EOL.

[Murray Stokely]

  I'm interested in writing a minor mode for marking up man pages with
the mdoc macros.  One of the things I would like to do is have
whitespace characters at the end of a nonblank line show up in a
different color, so I can easily notice (and remove) these stray marks
(which can easily be done with a macro, but thats not the point).

  I don't need to setup a syntax table for something so trivial, do I?
Is there a good example minor mode to help learn some of this stuff?

   - Murray