The fastest I ever ran was a 4.69. Most of the times I was timed at high 4.7. I wasn't slow. I didn't have great speed but not slow. I saw 2 people run legit 4.4 in college. Both got drafted. The thing is, I was considered "below average speed" when playing ball in college. But after I quit and started playing intramurals, I was BY FAR the fastest out there...and that was after I stopped conditioning, started drinking a lot of beer and gaining weight.
The people that say they run 4.6 or less are completely full of shit. I don't believe any body that tells me that really...
I was in the same boat as you. I was always in that 4.6-4.7 range in my prime days (early 20's), although I always felt like I played faster on the field than in a timed run. When playing/running with all the lighter black guys either in organized sports or varisty athletics classes, I was never the fastest although I thought I was pretty quick in general. But some of those dudes were just sick as far as vertical speed goes.
When I would play with 10-20 friends in the spring at a park in a flag fb game or like you said, on the intramural fields, I was usually the fastest out there 99 of 100 times. But on the organized sports team? Not hardly. Top 20% on a lucky day. People that haven't done it (yes I am looking at you John Clayton, Todd McShay, Mike Mayock), don't realize how truly fast D1 CFB and NFL players are.
JR is right - it makes what Bo and Deion did even more amazing. Same goes for Vick, Joey Galloway and Chris Johnson. To me Darrell Green is the one of the most amazing specimens that football has ever seen. To run sub 4.5 electronically over 40 - just sickening.