Glass Delegate implementaion

DelegatePropertyConfiguration

public class DelegatePropertyConfiguration<T>: AbstractPropertyConfiguration where T : AbstractDataMappingContext
{
  /// <summary>
  /// The default Constructor.
  /// </summary>
  public DelegatePropertyConfiguration()
  {
  }

  public Action<T> MapToCmsAction { get; set; }

  public Func<T, object> MapToPropertyAction { get; set; }
    
}

SitecoreDelegate

public class SitecoreDelegate<T> : AbstractPropertyBuilder<T, SitecoreDelegatePropertyConfiguration>
{
  public SitecoreDelegate(Expression<Func<T, object>> ex): base(ex){}

  public SitecoreDelegate<T> SetValue(Action<SitecoreDataMappingContext> mapAction)
  {
      this.Configuration.MapToCmsAction = mapAction;
      return this;
  }

  public SitecoreDelegate<T> GetValue(Func<SitecoreDataMappingContext,object> mapFunction)
  {
      this.Configuration.MapToPropertyAction = mapFunction;
      return this;
  }
}

SitecoreDelegatePropertyConfiguration

public class SitecoreDelegatePropertyConfiguration : DelegatePropertyConfiguration<SitecoreDataMappingContext>
{
  /// <summary>
  /// The default Constructor.
  /// </summary>
  public SitecoreDelegatePropertyConfiguration()
  {
  }
}

SitecoreTypeExtensions

public static class SitecoreTypeExtensions
{
  public static SitecoreDelegate<T> Delegate<T>(this SitecoreType<T> type, Expression<Func<T, object>> ex)
  {
      var sitecoreDelegate = new SitecoreDelegate<T>(ex);
      type.Config.AddProperty(sitecoreDelegate.Configuration);
      return sitecoreDelegate;
  }
}

I have nuget packages available for this as well as glass using Agnostic Ioc on private feeds and my mapping framework if you would like to mess around some more.