I have traveled to Israel many, many times in the last few years. More times than not, they have weighed my carry-on, so get the LIGHTEST piece of luggage you can. I personally use a nylon tote bag that weighs next to nothing and schlep it myself. They also will let you carry a small pocketbook AND/OR a laptop bag or a backpack, provided it is not too large and does not look too heavy, otherwise they WILL weigh it and take it away.
Personally, I always wear a coat with huge pockets and put the heavy stuff I need on the plane, in my pockets.
Remember, there is now a second security check at the gate and you will have to re-open your carry on bags at that time.
However, I have often seen women carrying a shaitel box or a man carrying a hat box in addition to the normal carryon items, and they seem to get away with it.
Just a piece of information, if you want/need your carryon above your head, you need to board EARLY, since everyone has so much stuff, plus winter coats & hats now, that have to be stored, otherwise the stewardesses will put your luggage whereever there is room, and you could be the last one off the plane (a serious problem with connecting flights)