My fellow soldiers are I are instructed to leave our Humvees idling when driving them for various reasons - losing radio frequencies, air-conditioning, etc. However, if a stop-start system could be retrofitted to Humvees across the military (excepting those in Iraq and Afghanistan), we could save untold gallons of diesel that would otherwise be idled away without providing any benefit. With a light hybrid system, the electronics (such as our tactical radios and a/c) could run off the batteries. Additionally, the software controlling this could automatically start the diesel to 'top off' the batteries when they were close to running out of juice. I'm not proposing switching over to a hybrid drivetrain, just a system that would power the auxiliary electrics when the vehicle isn't in 'Drive.'
This system could also be fitted to the upcoming Humvee replacements. If Porsche can make this work in $100,000 sports cars, the DoD should be able to make this work for Humvees.