MiniProfiler.UmbracoMvc proof of concept. Blogpost here: http://www.mortenbock.dk/post/Profiling-MVC-views-in-Umbraco-6

Bootstrapper.cs

using System.Web.Mvc;
using Umbraco.Core;
using Umbraco.Web.Mvc;

namespace UmbMvcMiniProfiler
{
    public class Bootstrapper : ApplicationEventHandler
    {
        protected override void ApplicationStarting(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
        {
            ViewEngines.Engines.Clear();
            ViewEngines.Engines.Add(new MyProfilingEngine(new RenderViewEngine()));
            ViewEngines.Engines.Add(new MyProfilingEngine(new PluginViewEngine()));
        }
    }
}

MyProfilingEngine.cs

using System.Web.Mvc;
using StackExchange.Profiling;

namespace UmbMvcMiniProfiler
{
    public class MyProfilingEngine : IViewEngine
    {
        private readonly IViewEngine _inner;
        private readonly string _name;

        public MyProfilingEngine(IViewEngine inner)
        {
            _inner = inner;
            _name = inner.GetType().Name;
        }

        public ViewEngineResult FindPartialView(ControllerContext controllerContext, string partialViewName, bool useCache)
        {
            using (MiniProfiler.Current.Step(string.Format("{0}.FindPartialView, {1},{2}", _name, partialViewName, useCache)))
            {
                return WrapResult(_inner.FindPartialView(controllerContext, partialViewName, useCache));
            }
        }

        public ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache)
        {
            using (MiniProfiler.Current.Step(string.Format("{0}.FindView, {1},{2},{3}", _name, viewName, masterName, useCache)))
            {
                return WrapResult(_inner.FindView(controllerContext, viewName, masterName, useCache));
            }
        }

        private static ViewEngineResult WrapResult(ViewEngineResult innerResult)
        {
            ViewEngineResult profiledResult = innerResult.View != null
                                                  ? new ViewEngineResult(new MyProfilingView(innerResult.View), innerResult.ViewEngine)
                                                  : new ViewEngineResult(innerResult.SearchedLocations);
            return profiledResult;
        }

        public void ReleaseView(ControllerContext controllerContext, IView view)
        {
            using (MiniProfiler.Current.Step(string.Format("{0}.ReleaseView, {1}", _name, view.GetType().Name)))
            {
                _inner.ReleaseView(controllerContext, view);
            }
        }
    }
}

MyProfilingView.cs

using System.IO;
using System.Web.Mvc;
using StackExchange.Profiling;

namespace UmbMvcMiniProfiler
{
    public class MyProfilingView : IView
    {
        private readonly IView _innerView;
        private readonly string _path;

        public MyProfilingView(IView innerView)
        {
            _innerView = innerView;
            _path = innerView is BuildManagerCompiledView
                        ? ((BuildManagerCompiledView) innerView).ViewPath
                        : "NoPath";
        }

        public void Render(ViewContext viewContext, TextWriter writer)
        {
            using (MiniProfiler.Current.Step(string.Format("Render: {0}", _path)))
            {
                _innerView.Render(viewContext, writer);
            }
        }
    }
}