You can still buy Super-8 and used 16mm films at Derann Film Services
in England:  http://www.derann.com/  They sell "reprint" modern films
in full length in the Super-8 format, even in Cinemascope format (which
needs the special anamorphic lens!).

I couldn't find any classic silent films, but made an inquiry about
that, and asked for sources of silent films other places.  They,
however, seem to have many films for the steam railway enthusiast for
some strange reason.  Why don't they have films for the mechanical
music enthusiast?  :-)

With the right projection equipment, a good screen, and the projector
in a separate room behind a glass,  you get a much better picture
quality and experience than even DVD on a large TV.

Unluckily digital sound never made it to the magnetic strips on the
Super-8 film, and the film with its magnetic strips moves too slow to
get very good sound quality, but it's good enough.  I believe you won't
think of that when you see the movie as it should be -- on real film!
(With silent films the sound is no problem, of course.)

Thomas Henden
Norway