Thanks to John for sending me this info.
In the video Reggie Bush 40 Yard Dash – Fastest 4.33 video, Bush is on a track surface and possibly wearing track spikes.
Fabian Washington recorded the fastest 40 yard dash at the 2005 NFL Combine with a time of 4.29 seconds. Unfortunately no videos are available.
Washington reportedly ran a 4.39 in the 40 yard dash as a Senior in high school.
He played three years at the University of Nebraska Lincoln before skipping his senior year to become a first round 2005 NFL Draft selection of the Oakland Raiders (pick #23).