static class SuperSinglton
{
     static object _sync = new object();
     static object _instance;
     public static object Instance 
     {
           get
           {
                return _instance;
           }
           set
           {
                 if (_instance == null)
                      lock(_sync)
                           if (_instance == null)
                                  _instance = value;
           }
     }
}

<register type="ILogger" mapTo="Logger">
	<lifetime type="singleton"></lifetime>
</register>

<register type="ILogger" mapTo="Logger">
	<lifetime type="transient"></lifetime>
</register>

using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.IO;
    using System.Threading;


    public class Singleton<TClass> where TClass : new()
    {
        protected Singleton() { }
        private sealed class SingletonClassCreator
        {
            private static readonly TClass instance = new TClass();
            public static TClass Instance { get { return instance; } }
        }

        public static TClass Instance
        {
            get { return SingletonClassCreator.Instance; }
        }
    }

    public class Test
    {
        public Test() { }
    }

    internal class Program
    {
        private static void Main(string[] args)
        {
            ThreadPool.QueueUserWorkItem((object sender) =>
                {
                    Console.WriteLine("Thread Id: {0} Singleton<Test>.Instance.GetHashCode(): {1}", Thread.CurrentThread.ManagedThreadId, Singleton<Test>.Instance.GetHashCode());
                });
            ThreadPool.QueueUserWorkItem((object sender) =>
                {
                    Console.WriteLine("Thread Id: {0} Singleton<Test>.Instance.GetHashCode(): {1}", Thread.CurrentThread.ManagedThreadId, new Test().GetHashCode());
                });
            Console.WriteLine("Thread Id: {0} Singleton<Test>.Instance.GetHashCode(): {1}", Thread.CurrentThread.ManagedThreadId, new Test().GetHashCode());
            Console.ReadLine();
        }
    }