New Post: Design-time support

I've managed to get Caliburn Micro to work nicely with Blend at design-time, using d:DesignInstance, by modifying the bootstrapper as follow:

        ///<summary>
        /// Overriding only to avoid a design-time error (see below)
        ///</summary>
        ///<returns></returns>
        protectedoverride IEnumerable<Assembly> SelectAssemblies()
        {
            if (Execute.InDesignMode)
            {
                var appDomain = AppDomain.CurrentDomain;
                var assemblies = appDomain.GetType()
                                     .GetMethod("GetAssemblies")
                                     .Invoke(appDomain, null) as Assembly[] ?? new Assembly[] {};

                // the following original line raises an exception at design time so I've commented it and substituted for the lines that follow
                // var applicationAssembly = assemblies.LastOrDefault(x => !x.IsDynamic && x.GetExportedTypes().Any(t => t.IsSubclassOf(typeof(Application))));
                var applicationAssemblies = new List<Assembly>();
                foreach (var assemblyin assemblies)
                {
                    try
                    {
                        if (!assembly.IsDynamic && assembly.GetExportedTypes().Any(t => t.IsSubclassOf(typeof (Application))))
                            applicationAssemblies.Add(assembly);
                    }
                    catch (Exception)
                    {
                    }
                }
                return applicationAssemblies;
            }

            returnnew[] {Application.Current.GetType().Assembly};
        }

        ///<summary>
        /// Overriding to allow design-time ViewModel resolution
        ///</summary>
        protectedoverridevoid StartDesignTime()
        {
            base.StartDesignTime();

            var actual = ViewModelBinder.Bind;
            ViewModelBinder.Bind = (viewModel, view, context) =>
                {
                    var vmType = viewModel.GetType();
                    // when using d:DesignInstance, Blend tries to assign the DesignInstanceExtension class as the DataContext, so here we
                    // get the actual ViewModel which is in the Instance property of DesignInstanceExtension
                    if (vmType.FullName == "Microsoft.Expression.DesignModel.InstanceBuilders.DesignInstanceExtension")
                    {
                        var propInfo = vmType.GetProperty("Instance", BindingFlags.Instance | BindingFlags.NonPublic);
                        viewModel = propInfo.GetValue(viewModel, null);
                    }
                    actual(viewModel, view, context);
                };
        }

 Hope this helps anyone with design-time issues.