I've seen a few spares for sale on craigslist, but by the time you got 4 of them, for a little bit more cash, you could buy some Procomp black steelies with a proper offset and width. Perhaps try a junk yard?
There were some steel rims that came on Tacoma's and Tundra's in 16x7. I have seen a few of those for sale on craigslist, too.
