public abstract class Entity<TId>
{
    public virtual TId Id { get; protected set; }
    public override bool Equals(object obj)
    {
        return Equals(obj as Entity<TId>);
    }

    private static bool IsTransient(Entity<TId> obj)
    {
        return obj != null &&
        Equals(obj.Id, default(TId));
    }

    private Type GetUnproxiedType()
    {
        return GetType();
    }

    public virtual bool Equals(Entity<TId> other)
    {
        if (other == null)
            return false;
        if (ReferenceEquals(this, other))
            return true;
        if (!IsTransient(this) &&
        !IsTransient(other) &&
        Equals(Id, other.Id))
        {
            var otherType = other.GetUnproxiedType();
            var thisType = GetUnproxiedType();
            return thisType.IsAssignableFrom(otherType) ||
            otherType.IsAssignableFrom(thisType);
        }
        return false;
    }

    public override int GetHashCode()
    {
        if (Equals(Id, default(TId)))
            return base.GetHashCode();
        return Id.GetHashCode();
    }
}

public abstract class Entity : Entity<Guid>
{
}

using System;

namespace ConsoleApplication22
{
    class Program
    {
        static void Main(string[] args)
        {
            var v = new Proxy();
            var v2 = new Proxy();
            v.Equals(v2);
            Console.ReadKey();
        }
    }

    abstract class Entity
    {
        private Type GetUnproxiedType()
        { return GetType(); }

        public override bool Equals(object o)
        {
            var other = o as Entity;

            Console.WriteLine(other.GetType());
            Console.WriteLine(other.GetUnproxiedType());

            return true;
        }
    }

    class Product : Entity
    {
    }

    class Proxy : Product
    {
    }
}

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