Now I wonder if something similar is possible with the magnetic fields on VHS tape

Thoughts on that: (1) you'd need a way to visualize the magnetic fields, (2) the data is frequency modulated, (3) due to helical scan, the video field lines do not line up evenly one over the next as they did so nicely in the Laserdisc / CED (there'd be a skew).

So I don't want to say it's impossible, but I think it would require a lot more creativity.