Thanks for the tip, 2old_honda, I'll definitely check into that.
Here's pics of the fan ducted with the aluminum tape:
And here's it in action.
Please note the waterblock you see is
temporary. I can't comment on performance since I don't have an accurate means of measuring yet, but it seems to do a lot better than my PAL8045.
I'm still figuring out how the acrylic casing will be constructed, but I'm just happy it's running right now.
BTW: The fan is actually spinning in those pics, just at a very low RPM.