Combobox as a search.. possible?

I saw in the archives where this was asked once before, but never answered,
so here goes…

Can I set up a custom field combobox to display as a combobox in the ticket
search area? Currently, it only displays the custom field as a text entry
when searching, but I’d rather have the combobox functionality in search. I
have it in ticket creation, works fine there… just want it in search as
well. Is this possible?