Just want to throw this out there for discussion, would any of ye pay to have these tested? There are other testing options also, but the test below seem to be the the full package for running related tests:
Lactate threshold test with VO2 In addition to the measurement of blood lactate, this assessment also measures metabolic and ventilatory data during incremental exercise. Gas exchange will be measured using a metabolic cart to determine oxygen consumption and carbon dioxide production. Other variables measured include ventilation rate, max heart rate, and VO2max, the maximal amount of oxygen the body can consume to produce energy. $200
More info here from the clinic:
http://www.fortiussport.com/Services/Pages/ExercisePhysiology.aspx
I'm thinking of doing it at some stage, as I'm curious about these things but don't necessarily want to know my limits. I'd like to think with enough training, I can be as fast as a Kenyan

A mod may want to add a poll to the thread to guage responses....