I don't know of any. How about using small pins? Drive them in to the
proper height, and solder the rail to the top. This method goes back to
the Olden Days, before there were any rail chairs.
And to represent the insulators pop into one of those bead shops that
support that jewelry making hobby, should be able to find some small
beads with a hole through that will look a reasonable shape.
They often have some interesting bits that may be useful in other ways
too. Those springy press stud thingies can make ideal bogie mounts in
some circumstances and fine wire for handrails etc is available in
various sizes. My missus won't take me along now, Says I'm a
distraction as I say "I can use that for xxxxxxx"