The "Virginia ham" in Chinese markets is a pretty close substitute as I understand it. I've seen it cut in the refrigerator case in slices of 0.5-1.0 lb at Sunset Super. A little goes quite a long way.
also at the Chinese market on Clement Street, next to the parking lot in the same block as the 4-Star movie theater (not the produce market, the tiny meat-poultry-fish market at the west end of the string of shops)
I know well enough that it's produced in a suburb of Shanghai, having been to China a dozen times. I've even smuggled some back myself. . But it cannot be legally imported, and I've seen cured Smithfield ham slices sometimes signed as "Jinhua" ham in Chinese characters.
If you open the link and read what I posted and look at the photo, you'll see that the brands sold at the Chinese markets are well-known Smithfield brands. The domestic ethnic Chinese market is a significant niche for Smithfield and has been for many decades.
Ranch 99 carries Gwaltney Ham. It is a subsidiary of Smithfield and located right across the street from the Smithfield factory. I've been there many time. I can't honestly tell the difference between the two.