Was never sure if they were real or myth.
They are real.
http://specialoperations.com/28857/sof-backpack-nukes/
In the early eightites I was in a Division command post exercise they were part of the scenario.
Fascinating stuff!!
Great website.
There used to be rumors that the soviets already had men and suitcase nukes in the States. Dont know if that was myth or truth either.