I'm actually somewhat surprised that it took this long for someone to revive the Postal Nationals in the age of instant online results- it's a good, objective way of comparing distance teams nationally.
The all time list puts things in perspective nicely and is a handy reference for those "best team of all time" debates.
Stray observations-
If Hammond 74-75 had 2 more guys at 9:27y and 9:35y, how the hell did they only place 3rd at their state meet? Were one or both of those guys injured?
The girls AT list really brings home for me how much FM emphasizes cross over track; they've had 3 or 4 of the 5 best cross country teams of all time, but only 1 of the top 5 3200 averages.
11:10 is definitely too fast for the girls cutoff. Something more like 11:15-11:20 would be an equivalent performance to a boy running 10:00, but given the relative lack of depth on the girls side, something like 11:30 is probably about right.