I have a class named SSLXMLRPCServer. Should it be that or SslXmlRpcServer?
As stated already, PEP-8 says to use upper-case for acronym. Now, python zen also says "readability counts" (and for me the zen has priority over the PEP :-).
My opinion in such unclear situation is to take into account the standard in the programming context, not just the language. For example, some xml-http-query class should be written XMLHttpQuery in a servlet context (w.r.t XMLHttpRequest).
I don't know your context, but it seems XMLRPCServer exists and you want to attach ssl to it. So you could choose something like:
SSL_XMLRPCServer
It would emphasized the XMLRPCServer -without changing it-. 
Also, you'd stay close to PEP-8 and follow the zen :-)
My 2 cents
Note: if XMLRPCServer is not strongly related to your class and is really a standard in the domain, then you need to choose another name, as to not be confusing.
If my python class name has an acronym, should I keep it upper case, or only the first letter?