As you mentioned, metal pivots could be fitted and
some post-slicing
profiling shouldn't be difficult. I remember that our model shop guy
milled almost everything non-metallic out of polycarbonate; details
were always crisp and painting looked really good. Someone with a
well-equipped metal shop should be able to turn these things out
assembly-line style.
For this much trouble, it would probably be worth just making a proper mold.
For the paddle types, and maybe the others, I can see it would be
possible to make an el cheapo two part mold, then have a small amount
of milling of the finished parts. Two part molds are a whole bunch
cheaper than three part molds, which is probably what the originals
used.
--
Will