This post is from my friend Forrest who does a lot of lofi photography stuff. On top is his modified Holga and the bottom is a shot taken with it. I love how the exposure extends all the way to the edges.
"We all know the Holga can create some amazing 6×6 images, but did you know it can also use 35mm film? With a bit of ingenuity, foam, and tape, a Holga can be outfitted with 35mm film to create some spectacular photos. After developing, you can scan your negatives to catch the full effect of the Holga 35mm frame."
The Lomography site has a page about the Holga 35mm mod process which can be found here.