Hmm.  I own xml.com.  I have not to date actually put it to use, but
I plan to.  Nonetheless, as its owner, I am happy to offer it for
this purpose, and com.xml.sax has a nice ring.
If anyone is feeling paranoid, I would be happy to sign an undertaking
(a) never to interfere with or charge for this use of the xml.com
    namespace, and
(b) should I sell xml.com sometime, to require the buyer to sign up
    to conditions (a) and (b).
 -Tim