A Razor view engine that supports several methods of organizing views and controllers within the same folder.

ModularConventionViewEngine.cs

  public class ModularConventionViewEngine : RazorViewEngine
	{
		//This needs to be initialized to the root namespace of your MVC project.
		//Usually, the namespace of your Global.asax's codebehind will do the trick.
		private static readonly string RootNamespace = typeof(MvcApplication).Namespace;

		private static IEnumerable<string> GetPath(ControllerContext controllerContext, string viewName)
		{
			var paths = new List<string>();

			//TODO: Cache?
			var controllerType = controllerContext.Controller.GetType();
			var controllerName = controllerType.Name.Replace("Controller", string.Empty);
			var featureFolder = "~" + controllerType.Namespace.Replace(RootNamespace, string.Empty).Replace(".", "/");

			//View in the same folder as controller (controller-folder/view.cshtml)
			paths.Add(string.Format("{0}/{1}.cshtml", featureFolder, viewName));

			//View in a view-folder within controller-folder (controller-folder/views/view.cshtml)
			paths.Add(string.Format("{0}/Views/{1}.cshtml", featureFolder, viewName));

			//View in folder with controller name within a view-folder within a controller-folder (controller-folder/views/controller-name/view.cshtml)
			paths.Add(string.Format("{0}/Views/{1}/{2}.cshtml", featureFolder, controllerName, viewName));

			return paths;
		}

		public override ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache)
		{
			var paths = GetPath(controllerContext, viewName);
			var path = paths.FirstOrDefault(p => VirtualPathProvider.FileExists(p));

			if (path != null)
			{
				return new ViewEngineResult(CreateView(controllerContext, path, null), this);
			}
			//Check the usual suspects
			return base.FindView(controllerContext, viewName, masterName, useCache);
		}

		public override ViewEngineResult FindPartialView(ControllerContext controllerContext, string partialViewName, bool useCache)
		{
			var paths = GetPath(controllerContext, partialViewName);
			var path = paths.FirstOrDefault(p => VirtualPathProvider.FileExists(p));

			if (path != null)
			{
				return new ViewEngineResult(CreateView(controllerContext, path, null), this);
			}
			//check the usual suspects
			return base.FindPartialView(controllerContext, partialViewName, useCache);
		}
	}

Fix to render a partial as a partial not as a view

public override ViewEngineResult FindPartialView(ControllerContext controllerContext, string partialViewName, bool useCache)
{
    var path = GetPath(controllerContext, partialViewName);

    if (path != null)
    {
        return new ViewEngineResult(CreatePartialView(controllerContext, path), this);
    }
    //check the usual suspects
    return base.FindPartialView(controllerContext, partialViewName, useCache);
}