More like an impossible analysis to do properly.

Your suggestion for an analysis of comfort as a function of material assumes that there is such a function that is based on the inherent material properties. But the evidence is that such an assumption is wrong. The example given earlier of the Vitus 929 vs. Cannondale CAAD frames is instructive in this regard.

The Vitus frames were almost universally reviewed as being very flexible and giving a cushy, highly comfortable ride. Racers liked them for the light weight but some claimed that the flex made them inefficient. Nevertheless, they were raced successfully, so the efficiency can't have been all that bad. [And, BTW, the Vitus frames disprove the idea that Al frames must be stiff to be durable enough for bicycle use; some did have failures but those were almost all at the bonded joints.]

The Cannondale (and Klein) frames got exactly opposite reviews. Praised for being extremely stiff with no wasted energy going into flexing the frame. But some claimed that the lack of compliance made them too harsh riding and uncomfortable. Nevertheless, many were successfully used on long endurance event rides, so apparently the comfort can't have been that bad for everyone.

So two frames, made of the same material, can have diametrically opposite evaluations on the qualities of comfort and stiffness. Good luck on finding that 'comfort function' that's determined by choice of frame material.