Measurement for the downstream use of a commodity
If you are looking for certain commodity data from the US.  The USDA Economic Research Service has data on market size of certain commodities.  But I am not sure about firm level data.  

https://www.ers.usda.gov/data-products/commodity-costs-and-returns/

There measures include cost and return estimates are reported for the United States and major production regions for corn, soybeans, wheat, cotton, grain sorghum, rice, peanuts, oats, barley, milk, hogs, and cow-calf. The series of commodity cost and return estimates for the U.S. and regions is divided into two categories: Recent and Historical estimates. 

I am not sure if this is exactly what you are looking for but this is a good start.  One can also call their office for additional information.