The Bowery has a steel fork. Tightening the top cap made a difference for a while on mine but it did get to the stage that I couldn't tighten it anymore without the headset binding.
The way I checked once I'd ruled out the headset, bars, stem and wheel, was to take the fork out the frame and remove the brake caliper. I then put the fork face down on the floor and leant on it slightly at the point the brake attaches, then turned it round the other way and applied a bit pressure to the steerer and fork legs and it creaked. I turned it round again and applied some pressure at the brake mount again and it creaked. It seemed to creak in the fore/aft direction. There were no visible cracks or anything on the fork itself, and I even removed the crown race to rule that out of the equation, but once it was out of the frame and flexed a bit it was clear the fork itself was the problem.
I'm not saying that's what's wrong with yours but it's worth giving it a proper check. You can't always trust your LBS.