We've got two Jungles here, both are fairly placid in nature. One does get a bit flighty when anyone but his owner is handling him, but it's a matter of making your movements slow and obvious. If we think something will startle him, it probably will. My Jungle python Caine, was the snappiest hatchling of the two - they are brothers, but he's the 'calmest' one now. My sister, who's not too keen on handling any other snake but her own Darwin python, happily handles Caine when I ask her to, provided I remove him from his enclosure. He's not cage defensive mind you, she just doesn't like disturbing them.
If you've got your heart set on a Jungle, I wouldn't let their bad reputation for being aggressive affect your choice too much. All snakes have the capacity to be aggressive, or well, defensive, it's just a matter of how they are handled. True, there are snakes out there that are the spawn of satan regardless of how they are handled, but not all of them are Jungles.