I’ve wondered the same thing, and the answer appears to be no. Ild is a specific measurement, taken with a certain size core (6" thick I believe), and hardly even perfectly standardized at that.
I’ve wished you could tho… And it’s not an impossible measurement that I’d guess you’re looking for. But, nobody has done it. What I suspect you want is basically something more along the lines of:
For a given surface (i.e. a mattress), how many lbs force is required to reduce a square foot of its height by x inches, and then plot the graph for all values of x from 0 inches to some reasonable upper bound (maybe 3/4 of the mattress thickness) - sort of like a torque curve for car engines. Such a graph would combine the ild and compression modulus or whatever it’s called into a single graph, and could be applied to an entire mattress with all the layers, and not just a specific material. With multi zone mattresses, you’d have different areas of the mattress to test.
… But that’d be far too scientific, and arguably make it much easier to duplicate the feel of a mattress. You’d have a nice graph of exactly how much force required to sink in a little deeper.
This is something you could probably make some sort of smallish apparatus to measure to some degree, and test beds with. You’d look a bit strange mind you a string across the mattress to provide a reference level, a ‘foot’ measuring say 1x1, that you push down, and with a ruler on its side to measure the depression vs the string. A lbs scale on top you’re pushing on. Start at 0, then press in scale until foot is 0.5", 1", 1.5", 2", etc (or 0.25" increments) and record pounds of pressure off the scale. Not perfect but… Also, at some point it’ll get really hard to press further down so you might need to exert a lot of pressure to get some of the later readings.
…bonus points if you can time the readings too - pressure to compress, and pressure 5, 10, 15, 20, etc seconds after being compressed. Some materials, once compressed, will tend to stay compressed (I.e. It might take a lot of effort to compress, but once compressed it generally doesn’t push back as hard) (e.g. Memory foam?), whereas others tend to consistently push back (e.g. Latex)
…huge bonus points for doing it in reverse too (I.e. once compressed, if you let up x inches, how much pressure is required to hold it at the new level). This would help you capture how elastic / responsive the material is to return to its original form. E.g. Slow memory foam vs talalay latex.