Note there's already a couple of HTTPS servers in Lib/test/ssl_servers.py. I'm not sure there's anything special to do for XMLRPC except to take the core instantiation code and put it in xmlrpclib.
I've hacked this support in myself a few times with a simple socket wrap call in SimpleXMLRPCServer's __init__. I'd be happy to put a quick patch together if that's a viable approach. Is there any desire to support client authentication or advanced features like that? Or, are we simply looking for encryption?
The patch is out of date. The XMLRPC HTTPS server should accept a ssl context instead of key and cert file. This allows better customization and SSL session resumption.