There are some good documentaries on the VHS underground... like this one.
I have fond memories of going to the video store and looking at all the artwork
used for the movie cases and posters.
Not exactly what you are looking for...
I would be tempted to model a cube 254mm x 254mm x 1000mm or more high
then match the cube to the camera view as best as possible.
apply some ruler decals to the edge of the cube to see the measurements.