When you negotiate with amazon they do try to bring stock appreciation into it. It went like this:

I asked for X comp, say 100K total for 4 years, including stock. The recruiter calls me back, says she got the total I wanted, I write down the numbers and it totals to 90K. I ask her why the math does not check out and the answer was that the 'missing' 10K is the projected stock growth.

Haven't seen anything like that in other negotiations.