>>>"nonsense" answers from the few brushless motor controller manufacturers I contacted<<<

  ... and what kind of information you asked that they cannot answer? 

Charles,
I do agree that the info provided by the ESC manufacturers lacks detail that I would like to know.  You can see this from my question about how the governor mode works in another thread on this forum. Empirically (and from the posts by Dean P.), the Castle Creations Phoenix ESC at least counts frequency, but you can't really get this from the paperwork--not in clear terms anyway.
For example, I get the same rpm whether I use a 3 cell lipo or a 2 cell lipo without making any change to the timer/throttle. Of course this means I am running the 3 cell at something less than 2/3 throttle effectively. Actually it makes sense that these things count frequency since that is basically a digital function, whereas measuring actual current would be more sopisticated. A current limit is easier since that probably just uses a comparitor---at least that is my guess!

I plan to check out your links, but haven't had a chance yet.

Whether the speed control set-point was constant speed (frequency) or torque (current). I have since discovered one controller that I think does what I want (set frequency)

But when I asked the question as posed above - I did not get a real answer.

OK?

Did you check any of those app notes? Quite interesting and informative I thought

Charles

I also do not know what exactly you asking.

our ESC has 3 logical levels:
1/ on lowest level simulates DC commutator, means that lowest part od ESC and BLDC motor works exactly like a permanent magnet DC motor. Menaing that ususal AC efects like phase slip does not work here, the rpm control needs voltage or PWM controlling.

2/ Over is PWM regulation exactly like for DC motor, means PWM ratio is proportional to wanted power

3/ And even over that function we have governor which can measure actual shaft rpm (as it is implemented on the same processor) and regarding that rpm controlls PWM power to a fixed value proportional to input signal

The only fixed frequency is PWM.