I have a bunch of 20th Century Fox Home Entertainment Germany promotional slides and 35mm prints. Actually I have never really thought about framing my 35mm prints but I have framed one of the promotional slides. I've done it in a frame and went to a photo store to make a photo print. Then I bought a sheet of black paper. I cut out one hole for the print and another one for the slide. I taped the slide with crystal cleer tape and the print on a white paper sheet. Then I've done the black sheet and the white sheet together and framed it. You can clearly see the slide and if you want to get the details you can take a look on the print. Two film frames have, more or less, the same size as a single slide. If you cut two frames and put it in a slide frame you can get a print of it.
Here's a comparisson chart of the sizes:
btw, thats a Scan of the promotional slide:
If you want one, for your collection, drop me a line.
cu, Spaceball