Ah, sorry bout that. I have 6 bolt pattern on my beastie, even harder to find than the 10 bolts.
I would think that being a '70 with a 10 bolt pattern, you would be able to find someone still manufacturing 1-piece wheels. Again, check the local truck/farm shops, might be the best place to start.

1956 GMC 370 dump " 'Tater "
1970 VW Volksrod "the Black Bomber"
2007 Chevy Avalanche
2020 Jeep Cherokee Trailhawk,
2005 Harley Davidson FLHTCUI

I dig all cars, old and new, whether they were hammered out of American iron, German steel, or Japanese tin cans. Being unable to appreciate them all is missing out on a world of great things.
But thats just MY opinion! :P