Hello Charles,
Regarding these link buttons on the top of the list with RadComboBox items, you could use the header template.
In order to show the number of items selected when the drop-down of the RadComboBox is closed, you should subscribe on the OnClientDropDownClosing client-side event and used the following event handler function:
I hope this would help you out.
All the best,
Dimitar Terziev
the Telerik team