I vented my teklight fixture with a high CFM 120mm AC fan. I don't run the fan any more because it was so noisy, but even having the blowhole cut out improved the heat removal. A LOT of a heat comes out of the hole I cut out, despite there already being the slits there.
I think venting from the top is only half a solution, since the reflectors themselves prevent heat from escaping the bulbs. The unit relies on the aluminum reflectors to conduct the heat to the upper regions of the fixture. I think fans blowing directly onto the bulbs would be the best solution.
That's AFTER I change my bulbs though, and AFTER I get an dosing system, and AFTER I get a zeovit system, though
. not a high priority to air-cool my fixture.