i had a blade III 4m about 18 months ago now, it was a nice kite but i couldn't get many jumps out of it. i did tweak with the brake lines by tightening them by about an inch and that gave me loads more power.
i found it easier to jump with a 3.5 bullet, but that was because i could really speed the kite up, run with the kite then crank it in the opposite direction, which would get me in the air upto about 6ft and then drop like a stone!
maybe the answer is to go for a larger kite. i'm looking at the mac bego at the moment, haven't tried one yet but they have loads of lift and an excellent write up:cool: