Any machine shop with a press brake can bend you some out of bar stock, and punch square holes in them. Probably lots cheaper than having them cast, esp. if patterns have to be made for each.
I made mine from 3/8" silicon bronze plate, cut with a plasma cutter
at a local college, and bent on their press brake. The main ones have two bends: one out from the hull
, the other around the chainwale. Not as elegant as a custom casting, but lots more affordable, and plenty strong.