I've never seen a Modulus, I might have to go to see Steve at Hunts and ask if he has one. Probably somewhat superior to my efforts with a Bosch hammer drill tbh! It's too damn cold to hang out in the garage right now, so this project will have to wait for a few months yet.
Tell us more about the ping machine.
Best photo of a Modulus I could find, basically channels cut in the back of the bat and then filled with a honeycomb insert to keep the stiffness of the blade while losing weight. Worked well iirc but obviously the ICC ban hammer came down.
Regards ping testing - all you need is a machine or arm that will swing the bat at a set speed and a method of measuring the resulting ball speed; high speed camera plus a graduated background or similar. It's then reasonably simple maths to convert that speed result into a value of coefficient of restitution for the bat (i.e. ping). Plenty of research labs have this setup in some form or other for sports testing, in baseball there's even a testing standard for non-wooden bats.
Problems with cricket - wood's a natural product so even if one example of a bat model produces a certain result, another may not. How much do you knock it in pre-test, etc etc. Balls are also not very heavily regulated so you'd get very different results due to variations in balls. In a potential future where we ditch willow and bats are made from composites COR would be very useful indeed but probably isn't now. Also, the middle position on cricket bats varies - to have a standardised test you'd need a set impact point, which would potentially discriminate against bats that had different middles. To be honest, the effect of middle position on cor would be far more interesting than just looking at ping!
On a more mundane note, a ruler and a camera would do the job - drop a ball on a bat from a set height and measure how high it bounces.