ASP.NET repeater alternate row highlighting without full blown <alternatingitemtemplate/>

I'm trying to accomplish simply adding a css class to a div on alternate rows in my <itemtemplate/> without going to the overhead of including a full blown <alternatingitemtemplate/> which will force me to keep a lot of markup in sync in the future.

I've seen a solution such as http://blog.net-tutorials.com/2009/04/02/how-to-alternate-row-color-with-the-aspnet-repeater-control/ which I'm tempted to use but this still doesn't "smell" right to me.

Has anyone else got a more maintainable and straightforward solution? Ideally I'd like to be able to do something like:

<asp:repeater id="repeaterOptions" runat="server">
        <headertemplate>
            <div class="divtable">
                <h2>Other Options</h2>
        </headertemplate>
        <itemtemplate>
                <div class="item <%# IsAlternatingRow ? "dark" : "light" %>">

But I can't figure out how to implement IsAlternatingRow - even with extension methods.