Actually, you could do almost exactly the same with RadComboBox, except that you will have a dropdown button... :) Most probably we will extend our combo with the advanced features of the autocomplete box in the upcoming updates of RadControls.
I am quite busy near the release, but on my schedule I have an example, demonstrating how to implement autocomplete with RadComboBox and an ADO.NET Data Service (my favorite kind of service). If I get bored with the development of our new online examples application (yes, we are going to refresh it!) this weekend, I could create the example and blog about it.
the Telerik team
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