It would be really cool if you could implement soap binding using the same xml library.
ZSI offers soap's http binding, and core soap api for binding to other protocols (e.g. xmpp), but its based on no longer supported PyXML module.
http://www.xmpp.org/extensions/xep-0072.html
let me know what you think. the soap binding would really extend the usability of xmpp as it provides easy api for developing custom server-client applications that scale beyond messaging, mail, exchanging files.
It lets you easily exchange data of any format.
And xmpp protocol is perfect as it doesn't have the http's limitations of request->response types of data exchanges.