I don’t think they are radio amateurs, but these guys seem to have The Knack. That’s an edge-of-space balloon payload they built. They plan to launch on May 31. You will be able to follow the event live, on-line. They have a very interesting web site: http://spacebits.eu/
If you like this stuff also have a look here: http://www.ballonvossenjacht.nl/ This is the yearly balloon fox hunt in The Netherlands. Height is up to about 10Km I believe. An ambitious European project involving several balloons is here: http://www.balloonproject.eu/ 26.06.2010 seems to be the next launch. Joop – pe1cqp