Hey, All! Some good news...
There is a CALIBRATED Mic that is very close, if not identical to the Behringer or Nady. It comes with a real calibration file!
It is the Dayton Audio EMM-6 Electret Measurement Microphone. From Parts-Express. It's only $48 and that cal file is really handy. When used with Fuzzmeasure 3 on a Mac and an inexpensive ART USB powered mic preamp, you insert the cal file in the measurements and it subtracts out to perfectly flat from 20Hz to 20KHz.
How's THAT for an inexpensive yet effective measuring system? Thank you PE and Dayton!
I use it daily with my speaker systems, both for production and R&D. You can see what we're up to at holisticaudio.com