Check your headset bearings. In lots of cases in my experience(humid climates & sweaty riders) after I eliminate the BB as the source of creaking I pull the stem and spacers to find a rusty nasty headset bearings. Its sounds to me as if the creak is non rotational, however not being able to emulate it in the stand doesn't completely rule anything out. I'd bet on the headset though. Check it out and report back. Im curious. Are you torqueing the non-drive side arm on?