As far as ONC RPC (9.26: How can I do RPC in Perl?) came up in RPC ONC just recently. By the OP's followup they wound up using SWIG around what the C rpcgen produced, so what's on CPAN's currently crufty apparently.

Of course the answer also depends on what one means by "RPC". If DCE or ONC, then the current answer's a bit out of date. One might also appreciate a mention of other forms of calling remote code such as XML-RPC (RPC::XML), SOAP (SOAP::Lite), and CORBA (CORBA::MICO). Maybe even a passing mention of POE::Component::IKC::Client if interoperability with other languages isn't a concern.