I just got 4 16x6 wheels from Stockton Wheel in Stockton California. They worked out great. Kind of pricy, and a long lead time, but they'll make you a wheel with any backspacing you want.
They also offer a service to cut the centers out of your stock wheels, and weld them into modern rims. Keep your hubcaps, and run tubeless radials. Pretty cool.
Anyway I searched for years to find a 16" 8-lug wheel to fit my 52 1-ton. Finally got sick of looking.
-J