I have used reflective paper (can come with a 'stcky' back - it has a
protective coat you peel off) - if 'mylar' wasn't copyrighted - I would call
it mylar paper. I have used it for anamorphic drawings (relfective
cylinders) - and it has been fine. You can find it at an art supply store
that carries specialty papers. I don't think it was very expensive - we
mounted it on mat board to make the mirrors. I have also used spray adhesive
on overhead transparency sheets and mounted them on light blue and gray
paper... it was so-so.