Attached are some potential new routines for PDL::Graphics::PLplot.
1) imag (but doesn't do FITS headers yet)
2) xyplot2 (for having multiple line-drawing calls NOT appear on the same graph, but instead refresh, most useful for interactive devices)
3) held, hold, and release (ala PDL::Graphics::PGPLOT, for controlling when a subpage is advanced, an interactive device is refreshed, or a subsequent plot is made over the first)
I haven't worked with these in some time, but sent them to Doug Hunt back before P::G::PLplot was under pdl's git source control. You may find them useful.
They are demonstrated in the accompanying refresh subroutine.