Subscribing.
There are so many variables I suspect it would be difficult to narrow down the categories of expenses making up the production costs.
Even with the same people, same gear, the cost can vary wildly on many variables, such as wood, time of the year, location (if that changes and not buying in cordwood to a fixed location), etc. I've gear set up for very small trees/logs, and then other gear for medium sized logs and am missing gear to handle large logs.
At least if focussing on cordwood logs and a fixed location, it might be easier to form a consensus on the costs.
In that scenario, it'll be interesting to see how the costs vary with differing processing machinery. I mean, say you were feeding a cordking 20-30 model, knocking out 5 cords per hour, with a skidsteer to support the processor and two people (one for each machine). What does that work out per cord compared to a single operator bucking and splitting with a chainsaw and timberwolf or supersplit and a conveyor?
But then, the actual production and machinery/labour needed is just one part of the cost of a cord of firewood. Maintaining that gear, depreciation, electric or dinosaur, the land and building or lease costs, loading the wood for deliveries, delivery vehicles, someone manning the phones and dotting i's and crossing t's, etc.
How long is a piece of string?