I know the ISS is moving at ~27,600 km/h and is ~10 times further away than this jump, but is there a significant engineering reason to not say... double this jumps height? 5x? ...10x?
If you want to go higher, you're going to need to use a rocket instead of a gas-filled balloon.
And the balloon has to have a smaller density than the surrounding air to be floating.
http://www.nbcnews.com/id/6714639/ns/technology_and_science-...
Henry Spencer reckons it's been seriously considered all the way back, and he invented regular expressions, so, er, well apparently being a computer scientist gives you parachute credibility this week:
http://yarchive.net/space/launchers/personal_reentry.html
And there's some intriguing work from various people about using tethers as highly unconventional parachutes:
http://www.sciencedirect.com/science/article/pii/00945765950...