I look at the PP machines like I would at a traditional toolroom mill or a standard desktop 3D printer: Middle-ground compromises with relatively sharp upper limits (that can often be worked around by putting in way more work). I've actually been in contexts where even the standard PP-machines were too big.

However, I'd also like to have a bigger shredder and the approach of simplifying it an making it from available resources sounds great. Do you know if concepts like hacking leaf springs have been tried out in the PP project or in another context and if there are machines/blueprints available?

Btw: As far as I know, a lot of the design of the PP-machines has evolved by way of largely self-taught and more or less chaotic experimentation. So, it seemed to me that most of the development work on the machines is actually much closer to the contexts you refer to than it is to fibre lasers and specialized metallurgy.