I believe the Israeli bandage has a ?plastic bar by which you can thread the bandage material and double it back to apply additional pressure to the wound in question.
A few points to consider:
1. Ischaemic damage can occur with any kind of bandage tied tight enough. Even a t-shirt tied tight enough to stop any blood flow thru the area for a long enough time will cause ischaemic damage.

2. The point about hard objects probably refers to pressure necrosis. The soft part of the skin coming into contact with a hard object for a long enough time (your own body weight is enough to cause pressure sores) reduces the blood flow to the area in question and causes skin necrosis (death) over a longer period of time.

If the wound is severe enough to warrant an israeli type pressure bandage ( gunshot wound causing major arterial injury ), ischaemia of the limb is not the 1st consideration - stemming the life threatening blood loss is and hence the pressure requirement if the 1st dressing isn't doing its job. And if the pressure bandage doesn't stem the bleeding, the guy will be dead before ischaemia of the limb ever comes into the issue ! <img src="images/graemlins/grin.gif" alt="" />

Hope this helps!