The new scaffolding capabilities in ASP.NET web forms are great for productivity.

I'd like to see Telerik-specific scaffolding that substituted Telerik controls.

We need the exactly the same control that the guys over in Silverlight have:

http://www.telerik.com/products/silverlight/expressioneditor.aspx

I am in desperate need of this control in the ASP.Net platform.

I think you may consider the following similar type of control(s) in future release.  I think the following is a good fit for use between a BI solution and standard reports.  It gives regular users some flexibilities to generate ad-hoc queries within an application.

http://demo.easyquerybuilder.com/asp-net-ajax/

<telerik:RadMaskedTextBox ID="RadMaskedTextBox2" Runat="server" Mask="<0..255>.<0..255>.<0..255>.<0..255>" ZeroPadNumericRanges="false" PromptChar="">  
</telerik:RadMaskedTextBox> 

Should render 192.168.1.1 instead of 192.168.__1.__1 

The links in Preview mode should not be opened at all or at least opened automatically in a new window, so that user could preserve its content.

Possible resolution is to invoke the setTargetsForPreview method on the OnClientLoad event of the editor:

<telerik:RadEditor runat="server" ID="RadEditor1"
	 EditModes="Preview" OnClientLoad="OnClientLoad">
	<Content>
		<a href="http://www.telerik.com">Link</a>
	</Content>
</telerik:RadEditor>

<script type="text/javascript">
	function OnClientLoad(editor, args) {
		Telerik.Web.UI.Editor.Utils.setTargetsForPreview(editor);
	}
</script>

a radmenu  with input-fields would be very usefull
this would work the same way like a configuration-menu

It was bug in the Firefox, and now works as expected. Here is markup for testing:
<script runat="server">  
    protected void RadTextBox1_TextChanged(object sender, EventArgs e)
    {
        newText.Text = RadTextBox1.Text;
    }  
</script>
<asp:Label runat="server" ID="newText"></asp:Label>
<telerik:RadTextBox runat="server" ID="RadTextBox1" AutoPostBack="true" OnTextChanged="RadTextBox1_TextChanged"></telerik:RadTextBox>
<asp:Button Text="submit" runat="server" />

Has telerik ever thought of writing an SSO class or control that would allow someone to add the functionality to sign on to their website using sso and SAML 2.0 for secure login?

None of the demos are displaying correctly.  Take a look at: http://demos.telerik.com/aspnet-ajax/orgchart/examples/overview/defaultcs.aspx.  It appears that the stylesheet might be missing.

There is an on your live demo

http://demos.telerik.com/aspnet-ajax/grid/examples/columns-rows/rows/detailitemtemplate/defaultcs.aspx