You can try Advance Auto / Pep Boys You can also try Ebay, they have quite a
few listings for headlights and tail lights of the clear variety fior
Explorers.
If you want you can get the milky haze out of your existing lights by
sanding them

WAIT STOP you need special sandpaper up to 12000 grit and you also need
special polish to get the clear surface back, but you can do it.

Searcher1