Steve Ebersole, what I had in mind was an SPI interface such as:

public interface ParameterMetadataProvider {
    ParameterMetadata getParameterMetaData(String nativeQuery);
}

The default implementation would basically be the one from QueryPlanCache#buildParameterMetadata(), while OGM could plug in alternative implementations through the service registry.

I would like to send a pull request if you agree on that approach.