Telerik PanelBar for ASP.NET MVC supports right-to-left languages.

The only necessary change to enable this mode is to add a t-panelbar-rtl class to the panelbar:

<%= Html.Telerik().PanelBar()
        .Name("PanelBar")
        .HtmlAttributes(new { @class = "t-panelbar-rtl" })
        ...
%>