A generic singleton

What do you think about this for a generic singleton?

using System;
using System.Reflection;

/* Use like this
public class Highlander : Singleton
{
    private Highlander()
    {
        Console.WriteLine("There can be only one...");
    }
}*/

public class Singleton where T : class
{
    private static T instance;
    private static object initLock = new object();

    public static T GetInstance()
    {
        if (instance == null)
            CreateInstance();

        return instance;
    }

    private static void CreateInstance()
    {
        lock (initLock)
        {
            if (instance == null)
            {
                Type t = typeof(T);

                // Ensure there are no public constructors...
                ConstructorInfo[] ctors = t.GetConstructors();
                if (ctors.Length > 0)
                {
                   throw new InvalidOperationException(String.Format("
                       {0} has at least one accesible ctor making it impossible
                       to enforce singleton behaviour", t.Name));
                }

                // Create an instance via the private constructor
                instance = (T)Activator.CreateInstance(t, true);
            }
        }
    }
}

Since we have .NET 4, we could make use of Lazy

public class Singleton where T : class, new()
{
    private Singleton() {}

    private static readonly Lazy instance = new Lazy(() => new T());

    public static T Instance { get { return instance.Value; } } 
}

StackExchange Code Review Q#10554, answer score: 6