To my knowledge, no one makes them. You can get fiberglass, but not metal.
~ Victor 1941 3/4-Ton Pickup (in process). Read about it in the DITY Gallery 1955 Grumman Kurbside "Doughboy" 235/3 on tree w/ OD 1957 3100 - moved on 1959 C4500 Short Bus "Magic Bus" - moved on 1959 G3800 1 Ton Dually "Chief" - moved on 1958 C4400 Viking "Thor" ~ moved on to fellow Bolter
That's Brent Click that made those, he's in SC. Julian must be his "marketing agent" as Brent mainly just fabricates. You should also be able to find someone in CA that can make those from scratch for you, if that's what you want to do.