Actually we did do the brick-on-the-gas test for the very first Lemons in '06. We gave teams a chance to build a throttle stop with the caveat that they had to drive the car immediately from the brick-on-the-throttle test to the mannequin slalom. So, you wanted the stop to hold the car to about 3-4k rpm in neutral so you could actually drive through the slalom afterward.
The most hilarious part about this was the 30 minutes before the test when you could hear team testing their throttle stops in the pits with varying degrees of success. There was a lot of "OK, try it now," followed by an engine revving out of control, followed by "OH GOD, STOP, STOP!" followed by "I CAN'T, IT'S STUCK!!" Pretty great stuff.
Alas, both the rod-throw-apalooza and the mannequin slalom were eliminated due to the logistics of 100+ car fields and most everyone wanting to skip any kind of qualifying in favor of more race time.