There's a mod group located here:
http://lostbrothers.ofpmatch.comThey are creating an Israeli/Arab mod for OFP, so my guess is that they have the SF aspect of the IDF covered pretty well in addition to all the rest...
Unfortunately the mod site is down for the time being, so you'll just have to check back now and again to see if it works.
Other than that, there are some older Israeli soldier addons floating about, but they look quite dated compared to some of the new stuff that's looming around the corner.
This site has a Sayeret Matkal addon:
http://www.vit.run.to/I've never tried it, so i don't know if it's any good...
Cheers!