From: Moises Lejter <moilejter_at_gmail.com>
Date: Thu, 14 Jan 2010 10:45:45 -0500

I'm thinking what you want is to do is (1) have your clients specify
different acceptable MIME types, depending on whether they want heavy- or
light-weight responses, then have your own MessageBodyWriters for each of
the MIME types you define (on top of the built-in "application/xml" ...

Moises