Seems fixed indeed. Tested the following script:

import xmlrpclib
e = xmlrpclib.Fault("Error", "Message")
((d,), _) = xmlrpclib.loads(xmlrpclib.dumps((e,)))
assert d['faultString'] == "Message"

which works with python2.4, fails with python2.5, and works again with
python 2.6a0.

Now, this is a bug in 2.5, but the fix can be considered as a new
feature. I don't know if we should backport this.