How to implement and extend Joshua's builder pattern in .net?

public class NutritionFacts
    {
        public static NutritionFacts.Builder Build(string name, int servingSize, int servingsPerContainer)
        {
            return new NutritionFacts.Builder(name, servingSize, servingsPerContainer);
        }

        public sealed class Builder
        {
            public Builder(String name, int servingSize,
            int servingsPerContainer)
            {
            }
            public Builder totalFat(int val) { }
            public Builder saturatedFat(int val) { }
            public Builder transFat(int val) { }
            public Builder cholesterol(int val) { }
            //... 15 more setters
            public NutritionFacts build()
            {
                return new NutritionFacts(this);
            }
        }
        private NutritionFacts(Builder builder) { }
        protected NutritionFacts() { }
    }

public class MoreNutritionFacts : NutritionFacts
{
    public new static MoreNutritionFacts.Builder Build(string name, int servingSize, int servingsPerContainer)
    {
        return new MoreNutritionFacts.Builder(name, servingSize, servingsPerContainer);
    }
    public new sealed class Builder
    {
        public Builder(String name, int servingSize,
        int servingsPerContainer) {}
        public Builder totalFat(int val) { }
        public Builder saturatedFat(int val) { }
        public Builder transFat(int val) { }
        public Builder cholesterol(int val) { }
        //... 15 more setters
        public Builder newProperty(int val) { }
        public MoreNutritionFacts build()
        {
            return new MoreNutritionFacts(this);
        }
    }
    private MoreNutritionFacts(MoreNutritionFacts.Builder builder) { }
}

public class CustomerBuilder
{

   ......

   public static implicit operator Customer( CustomerBuilder builder )
   {
      return builder.Build();
   }
}

public sealed class SomeMessage
{
  public string Name { get; private set; }
  public int Age { get; private set; }

  // Can only be called in this class and nested types
  private SomeMessage() {}

  public sealed class Builder
  {
    private SomeMessage message = new SomeMessage();

    public string Name
    {
      get { return message.Name; }
      set { message.Name = value; }
    }

    public int Age
    {
      get { return message.Age; }
      set { message.Age = value; }
    }

    public SomeMessage Build()
    {
      // Check for optional fields etc here
      SomeMessage ret = message;
      message = null; // Builder is invalid after this
      return ret;
    }
  }
}

public interface IFactory<T>
{
    T Create();
}

public interface IBuilder<T> : IFactory<T>
{
    bool HasInstance { get; }

    T Instance { get; }

    void ClearInstance();
}

public abstract class Builder<T> : IBuilder<T>
{
    public static implicit operator T(Builder<T> builder)
    {
        return builder.Instance;
    }

    T _instance;

    public abstract T Create();

    public bool HasInstance { get; private set; }

    public T Instance
    {
        get
        {
            if(!this.HasInstance)
            {
                _instance = Create();

                this.HasInstance = true;
            }

            return _instance;
        }
    }

    public void ClearInstance()
    {
        this.HasInstance = false;

        _instance = default(T);
    }
}

public class Order
{
    public string ReferenceNumber { get; private set; }

    public DateTime? ApprovedDateTime { get; private set; }

    public void Approve()
    {
        this.ApprovedDateTime = DateTime.Now;
    }
}

public Order(string referenceNumber)
{
    // ... validate ...

    this.ReferenceNumber = referenceNumber;
}

internal Order(string referenceNumber, DateTime? approvedDateTime)
{
    this.ReferenceNumber = referenceNumber;
    this.ApprovedDateTime = approvedDateTime;
}

public class OrderBuilder : Builder<Order>
{
    string _referenceNumber;
    DateTime? _approvedDateTime;

    public override Order Create()
    {
        return new Order(_referenceNumber, _approvedDateTime);
    }

    public string ReferenceNumber
    {
        get { return _referenceNumber; }
        set
        {
            if(value != _referenceNumber)
            {
                _referenceNumber = value;

                ClearInstance();
            }
        }
    }

    public DateTime? ApprovedDateTime
    {
        get { return _approvedDateTime; }
        set
        {
            if(value != _approvedDateTime)
            {
                _approvedDateTime = value;

                ClearInstance();
            }
        }
    }
}

Order order = new OrderBuilder
{
    ReferenceNumber = "ABC123",
    ApprovedDateTime = new DateTime(2008, 11, 25)
};

public class NutritionFacts
  {
    public int servingSize { get; private set; }
    public int servings { get; private set; }
    public int calories { get; private set; }
    public int fat { get; private set; }
    public int carbohydrate { get; private set; }
    public int sodium { get; private set; }

    public NutritionFacts(int servingSize, int servings, int calories = 0, int fat = 0, int carbohydrate = 0, int sodium = 0)
    {
      this.servingSize = servingSize;
      this.servings = servings;
      this.calories = calories;
      this.fat = fat;
      this.carbohydrate = carbohydrate;
      this.sodium = sodium;
    }
  }

NutritionFacts nf2 = new NutritionFacts(240, 2, calories: 100, fat: 40);