I'd have to say Ted Ginn. There are a lot of rumors that he recently ran a very very fast time at Athletes Performance in Arizona that backs up some of the semi-ridiculous rumors of his 4.06. I can't wait to see him at the combine because I think he could blow away history.
A time of that nature (4.10 ish) isn't actually impossible. Running this time may not necessarily mean a guy is faster then say, a 4.3 guy in a 100 m dash, but he may have very well perfected that which is necessary to run well through out 40 yards, from first step explosion, to second gear, with body position and stride.