Did you consider gzipping your XML (or YAML) packets ? Would the transfer time be acceptable in this case ?
That would add even more to the overhead of transcoding the transportlayer. Switching from XMLRPC to a json-based protocol reduced in a project of mine reduced the overhead 10-20fold - mainly because of reduced size and parsing efforts.
Diez -- http://mail.python.org/mailman/listinfo/python-list
