I am 99% certain that this is no longer a 'problem' for the current bindings available from Sourceforge. (However, the discussion seems to indicate that we need to update the bindings so that a single stream can be set to a different filename.) Of course, the PLplot bindings for Perl are not in their own Sourceforge project, so you'd never find them. :)

You can git them with this command:
git clone git://pdl.git.sourceforge.net/gitroot/pdl/pdl-graphics-plplot

Build instructions follow the standard incantation and are documented near the end of the README, which you can read without needing to download here:
http://pdl.git.sourceforge.net/git/gitweb.cgi?p=pdl/pdl-graphics-plplot;a=blob;f=README;h=8d760e984f6821a9191f519e7da75f4bfe6470b0;hb=HEAD

You can also browse the repository here:
http://pdl.git.sourceforge.net/git/gitweb.cgi?p=pdl/pdl-graphics-plplot;a=tree

Hope that helps!

- David