I would look for rectangle lights on any of the European sites.The Netherlands(Bemo),or MSW Germany.I have personally used these places before.They have a very large selection of truck parts,and accessories.I have purchased some Scania rear light bars,for use on 8-wheel tippers,that have been converted to UK specs.It may take some searching to find exactly what you want,but MSW zubehor(accessories),page 22 part number 126 00285,00286,00287 should be close.
I don't know how much any import costs maybe,but they are fairly cheap parts.