Using Umbraco.CodeGen with PublishedContentModel. Flipped a few core classes and methods to public for testing.

ApplicationEvents.cs

using Umbraco.Core;
using Umbraco.Core.Models.PublishedContent;
using Umbraco.Core.ObjectResolution;

namespace CodeGenTest.Web.App_Start
{
    public class ApplicationEvents : ApplicationEventHandler
    {
        protected override void ApplicationInitialized(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            ResolverBase<PublishedContentModelFactoryResolver>.Reset();
            PublishedContentModelFactoryResolver.Current =
                new PublishedContentModelFactoryResolver(new PublishedContentModelFactoryImpl());
        }
    }
}

Article.cs

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:4.0.30319.18051
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

namespace CodeGenTest.Web.Models.DocumentTypes
{
    using System;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using Umbraco.Core.Models;
    using Umbraco.Web;
    
    public partial class Article : Content
    {
        private string icon = "folder.gif";
        private string thumbnail = "folder.png";
        private string defaultTemplate = "Article";
        private string[] allowedTemplates = new string[] {
                "Article"};
        public Article(IPublishedContent content) : 
                base(content)
        {
        }
        [DataType("Numeric")]
        public virtual Int32 Rating
        {
            get
            {
                return Content.GetPropertyValue<Int32>("rating");
            }
        }
    }
}

Article.cshtml

@inherits CodeGenTest.Web.Models.UmbracoTemplatePage<CodeGenTest.Web.Models.DocumentTypes.Article>
@{
    Layout = "Layout.cshtml";
}

@Html.Partial("Heading")

<p>@Html.Raw(CurrentPage.Body)</p>

<p>@CurrentPage.Rating</p>

Content.cs

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:4.0.30319.18051
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

namespace CodeGenTest.Web.Models.DocumentTypes
{
    using System;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using Umbraco.Core.Models;
    using Umbraco.Web;
    
    public partial class Content : TypedModelBase
    {
        private string icon = "folder.gif";
        private string thumbnail = "folder.png";
        private bool allowAtRoot = true;
        private string defaultTemplate = "Content";
        private string[] allowedTemplates = new string[] {
                "Content"};
        private System.Type[] structure = new System.Type[] {
                typeof(Content),
                typeof(DeviantContent),
                typeof(Article)};
        public Content(IPublishedContent content) : 
                base(content)
        {
        }
        [DataType("Textstring")]
        public virtual String Heading
        {
            get
            {
                return Content.GetPropertyValue<String>("heading");
            }
        }
        [DataType("Richtext editor")]
        public virtual String Body
        {
            get
            {
                return Content.GetPropertyValue<String>("body");
            }
        }
    }
}

Content.cshtml

@inherits CodeGenTest.Web.Models.UmbracoTemplatePage<CodeGenTest.Web.Models.DocumentTypes.Content>
@{
    Layout = "Layout.cshtml";
}

@Html.Partial("Heading")

<p>@Html.Raw(CurrentPage.Body)</p>

Content.Partial.cs

namespace CodeGenTest.Web.Models.DocumentTypes
{
    public partial class Content : IContent
    {
    }
}

DeviantContent.cs

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:4.0.30319.18051
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

namespace CodeGenTest.Web.Models.DocumentTypes
{
    using System;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using Umbraco.Core.Models;
    using Umbraco.Web;
    
    public partial class DeviantContent : TypedModelBase
    {
        private string icon = "folder.gif";
        private string thumbnail = "folder.png";
        private string defaultTemplate = "Deviant";
        private string[] allowedTemplates = new string[] {
                "Deviant"};
        public DeviantContent(IPublishedContent content) : 
                base(content)
        {
        }
        [DataType("Textstring")]
        public virtual String Heading
        {
            get
            {
                return Content.GetPropertyValue<String>("heading");
            }
        }
    }
}

DeviantContent.Partial.cs

namespace CodeGenTest.Web.Models.DocumentTypes
{
    public partial class DeviantContent : IContent
    {
    }
}

DeviantPage.cshtml

@inherits CodeGenTest.Web.Models.UmbracoTemplatePage<CodeGenTest.Web.Models.DocumentTypes.DeviantContent>
@{
    Layout = "Layout.cshtml";
}

@Html.Partial("Heading")

Heading.cshtml

@inherits CodeGenTest.Web.Models.UmbracoTemplatePage<CodeGenTest.Web.Models.IContent>

<h2>@CurrentPage.Heading</h2>

IContent.cs

using Umbraco.Core.Models;

namespace CodeGenTest.Web.Models
{
    public interface IContent : IPublishedContent
    {
        string Heading { get; }
    }
}

Layout.cshtml

@inherits CodeGenTest.Web.Models.UmbracoTemplatePage<CodeGenTest.Web.Models.IContent>

<html>
    <head>
        <title>@CurrentPage.Heading</title>
    </head>
    <body>
        @RenderBody()
    </body>
</html>

TypedModelBase.cs

using Umbraco.Core.Models;
using Umbraco.Core.Models.PublishedContent;

namespace CodeGenTest.Web.Models
{
    public class TypedModelBase : PublishedContentModel
    {
        public TypedModelBase(IPublishedContent content) : base(content)
        {
        }
    }
}

UmbracoTemplatePage.cs

using Umbraco.Core.Models;
using Umbraco.Web.Mvc;

namespace CodeGenTest.Web.Models
{
    public abstract class UmbracoTemplatePage<T> : UmbracoTemplatePage
        where T : IPublishedContent
    {
        public new T CurrentPage { get { return (T) Model.Content; } }
    }
}