I don't know about internet sources or laws, but in general Arab affairs are left up to the Arabs. I just took a look through my telephone and at least four people in my address book have multiple wives. These are people that I know well enough to have in my address book. Two of them I'd call personal friends, one is an electrician, and another I buy my gas from. I could probably find more in there, and I certainly know of many more.
This is still not answering the question whether these are legally recognized wives; whether they have residenve./nationality rights, right to work, etc
Me again. I just googled for "beduin polygamy in israel", try it and you'll find all you need. It is ostensibly illegal but impossible to enforce. You should know that it's not restricted to only Beduin, I recently was at a West Bank gas station talking to a guy (in Arabic) who has recently married his second wife. There are Beduins in the West Bank, but this guy wasn't Beduin.