It can vary quite a bit. Im with ExpressJet and I have had a 8 hour overnight in Little Rock on the same trip I had a 36 hour overnight in Mexico City. Typically you will see a min rest overnight on the last night of the trip because at the end of your trip you are released to your domicile rest and the company is off the hook for ensuring you get adequate rest. I have never seen any "standups" or "high speed" overnights here at ExpressJet but from what I hear they are common practice at Mesa, Mesaba and others.