Its taken just under seven years, but today the W3C announced that the XML-binary Optimized Packaging (XOP), Message Transmission Optimization Mechanism (MTOM), and the Resource Representation SOAP Header Block (RRSHB) were announced today as W3C Technical Recommendations

The timing on this is perfect - I'm developing a profile for a well-known Public Sector standards organization that will result in a proof of concept.  More to come (including the code) very soon...