Hi,

Maybe you could register your own ContentArea renderer

 private static void ConfigureContainer(ConfigurationExpression container)
        {
            container.For<ContentAreaRenderer>().Use<AlloyContentAreaRenderer>();
        }


public class AlloyContentAreaRenderer : ContentAreaRenderer
    {
        protected override void RenderContentAreaItems(HtmlHelper htmlHelper, IEnumerable<ContentAreaItem> contentAreaItems)
        {
            var maxElements = htmlHelper.ViewContext.ViewData["maxElements"];
            if (maxElements != null)
            {
                contentAreaItems = contentAreaItems.Take((int)maxElements);
            }
            base.RenderContentAreaItems(htmlHelper, contentAreaItems);
        }
}

I didnt test this code.

Would also think about editor side to prevent more items to be created inside content area if maximum items exceeded..