As to the question, about finding an equivalence between calories for an hour lifting weights VS an hour on treadmill, I recall watching a researcher monitoring a face mask, breathing hose. I think the scientists use the oxygen consumption to get parameters related to calories consumed. My guess, also, is there might be some other processes...ie Pathelogical that allow short bursts (of physical performance) in absence of correlation with oxygen consumption.
Oxygen consumption, my speculation, would be able to be directly correlated, with the whole cellular energy equation, almost literally molecule by molecule.
I think there must be ways of answering your question, assuming you get all the circumstances for comparing the two excercise activities.
For a similar reasoning, I probably would not look at a person's body weight (changes), as that could get complex. My guess is that body water loss, sweat, would make exact calorie studies hard to control, just solely on gross weight.
Perhaps, there are military conducted studies, that would supply those performance comparisons.
- Rick B