>Do any of you guys get paid on a royalty basis for this type of
>work?

        Yes.

        In fact, I find many small companies are enthusiastic about
        this type of arrangement because they feel it 'locks in' the
        contractor on a long-term basis.  By giving you a stake in
        the commercial success of the product, you naturally become
        more interested in ensuring its commercial viability.

        However, Andy's second law of contracting applies in spades.
        ONLY enter such arrangements with with _nice_ people (by which
        I mean people you can _trust_).

___Bob