I made a video delay with ofelia. It has 8 delayed frames (the distance between those frames is 1-36), and a frame buffer that stores the recent 300 frames. The frames are blended with a shader.
At the moment it first needs to fill the buffer before the video is drawn to the screen.
The frame buffer could be useful for other time based video effects like slit scan too.
ofeliaVideoDelay.zip
Here is a test, it can surely be optimized, but that is basically what I had in mind:

I was inspired by Norman McLarens "Pas de Deux" that makes use of the effect in a perfect way (and it was made without computers).
The effect has some similarity with my test around minute 9...

@Jona Thanks for sharing the patch and video.

The delay effect works nicely and it is pretty efficient to run the patch. (12~15% CPU usage)

@Cuinjune thanks for the library. I think it was really a good decision to change the Ofelia concept from version 1 to 2.
First I was a bit afraid of the scripting, because I was so used to the Pure Data patching style.
But I think it is much more flexible with the scripting now...