Don't worry I've experimented with this type of thing as well, so I won't critique your experiment.
Vantec ? Vantec Spectrum Fan Card - SP-FC70-BL - System Fan Card with Dual 70mm Adjustable UV LED Fans
That might do exactally what you want it to do.
With the bottom 120MM fan working in my HAF case, it actually lowers the second card by 7 degrees under idle and load. So the additional airflow does do something. Give what I linked a try Tigerdirect and NCIX should carry them. Might be worth a shot.
ST