Ok, but we've been running with a different focus. We're currently in progress of extending the formatter to include the ability to marshal ISerializable and [Serializable] objects in addition to structs for a better compatibility with the general Remoting framework. Tomas is also about to change the serializer to implement IRemotingFormatter - maybe we can merge some code later on!
Yes, the formatter code I've added to XML-RPC.NET just extends the library so that Remoting can be used instead of the existing web service-based approach. Its not designed to reproduce everything that Remoting does with respect to serializing data types, preferring instead to concentrate on maintaining interoperability with other XML-RPC implementations. The use of Remoting with XML-RPC.NET does offer a couple of advantages over the existing implementation: first, it enables you to run an XML-RPC server outside of IIS (as in the StateNameServer example), and second, it enables you to implement an XML-RPC server which can also accept SOAP requests.
I'm looking foward to seeing how Ingo and Tomas solve what looks like a considerably more complex challenge.