Open University (UK) had an educational filmstrip on the Periodic
Table that was distributed through Media Guild (San Diego, CA) years
ago.  It's great.  The narrator says "al-oo-minium" and refers to a
"very handsome lump of coal."  Contacting the company that took over
the Media Guild's collections and Open University were both dead ends.
 Where can I buy an acceptable quality copy of this filmstrip (or a
VHS version)?

I would be surprised that these ancient classroom mainstays even still
exist. I'm 30 and I had them in elementary school, but surely they no
longer exist.  (VHS is heading that way, too.)

Of course they still exist.  I use them in my classroom.  Admittedly,
they are in bad shape.  With the dearth of education funding in my
state, we are not exactly early adopters of new technology.  We have
projectors, record players, reel to reel players, and projectors. 
They were built when things were meant to last - and they were
fixable.  So, I want a copy of this fantastic filmstrip to show.