There are candidates on top of the list. But it depends on problem space. A quick look, Capnproto, by kenton varda, maybe a fit. CORBA is a bit old but used in many systems and frameworks such as ACE. One of the issues is PassByCopy of capability references which in capnproto PassByReference and PassByConstruction also provided. COM system also got some problems which needs it's own discussion. ZeroMQ is really cool which I caught a cold once. And it does not support RPC which means you have to implement it on level zero messaging. Also Google protobuf, kenton varda, could be a choice if you are not looking for features such as capabilities security, promise pipelining and other nice features provided by capnproto. I think you better give it a try and experiment yourself.
As a reminder, RPC is not only about remote object invocation. Areas of concern such as adequate level of abstraction and composition, pipelining, message passing, lambda calculus, capability security, ... are the important ones which have to be paid close attention. So, the better solution is finding the efficient and elegant one to your problem space.
Hope to be assistfull.
Bests,
Omid