Im having a similar issue mine seems more prevalent during down reving but it may be because my exhaust is drowning out the noise on the upside. Also its been getting louder progressively over the last 3-6 months (I cant remember exactly when it started). Also it definitely seems to be more prevalent when its done when car is not a full operating temps. Though nowadays there is slight noise all the time which leads me to believe its the alternator but not sure. Never considered the steering pump but that could be the issue as well.
My car is in the body shop for vandalism repairs but its going straight to the dealer when I get it back to look into this.
I'll come back to this thread once I let them take a look at it.