It shouldn’t be much work given that Service Broker is built around the same model of one-way, store and forward messaging.

You would implement the ITransport interface below, and configure it instead of the MsmqTransport implementation.

Does that answer your question?

using System;
using System.Collections.Generic;

namespace NServiceBus.Unicast.Transport
{
  public interface ITransport : IDisposable
  {
    void Start();
    IList MessageTypesToBeReceived { set; }

    int NumberOfWorkerThreads { get; }
    void ChangeNumberOfWorkerThreads(int targetNumberOfWorkerThreads);

    void Send(TransportMessage m, string destination);
    void ReceiveMessageLater(TransportMessage m);

    int GetNumberOfPendingMessages();

    string Address { get; }

    event EventHandler TransportMessageReceived;

   void AbortHandlingCurrentMessage();
  }
}