Steve's bang on the money here, when I changed systems from the H2 to the AFD II and III the first thing I noticed was the depth of the release button before it fired, quite different from the H2 and DSLR's... that is NOT a shutter lag problem, it's a user lag problem, once you hit the button it fires.
these camera's are high end bits of kit that require a user to get to know them, I shoot fashion, mostly with fast recycling Profoto packs, now you just don't shoot 'rat-a-tat-tat' in a studio, the lights need a little time to recharge, you get into a flow working with the lights, all this twaddle about micro second shutter lag is real world nonesense.
LEARN TO USE YOUR CAMERA. I have shot with both H2 and Mamiya AFDII's handheld at 1/60th with a 150mm on using natural light... 65% were fine 35% were not, but I'm asking for trouble going below 1/150th with a 150mm lens.
Buying kit doesn't make you a better shooter, using it does... dismissing an H2 with shutter slap is rubbish... the worlds TOP shooters use that camera, it and the Mamiya/Phase are now industry standard in NYC, London, Paris, Milan & Tokyo...
So maybe it's not the camera......?