Israeli Politics: Let's Make A Deal!

I've been patiently waiting for this moment, ever since I published a post 6 weeks ago laying out the coalition problems of one Benjamin Netanyahu.  Having prompted the March elections, having won a stunning victory over the Zionist Union and having trounced his rivals to his right, PM Netanyahu has for the moment become the weakest link.
A few minutes ago, Israeli politician Avigdor Lieberman announced that his small 6-seat party Yisrael Beitenu will not be joining the next government, and furthermore announced his resignation as Foreign Minister of Israel. "It's about principles," said the former bar bouncer, "it's not about [cabinet] chairs."
As things stand now (with a bit more than 48 hours to go before the mandated deadline for coalition formation), Netanyahu has a signed deal with 2 coalition partners: Moshe Kahlon's Kulanu party, and the ultra-Orthodox Yahadut ha-Torah. For those counting: that's a grand total of 46 seats - 15 short of a 61 seat majority. Supposedly waiting in the wings are two further parties - Aryeh Deri's Shas with 7 and Naftali Bennett's Bayit Yehudi with 8. But neither has signed yet, and are now smelling blood in the water.
There you have it - the minimum mathematical threshold for forming a government of 61. So now the fun begins. No sane PM would want a government of 61. Internationally, it projects weakness. Domestically, it means any single member of Kenesset (MK) in the coalition can plausibly threaten to bring it down - over a matter of policy, of money, or of "honor."
So what to do? Settle for 61 now, and hope to bring in more partners later? Siphon off a few disgruntled MKs from other parties? Go back to Lieberman and sweeten the pot in order to get to a slightly more respectable number of 67? Or turn to Buji Herzog and the Zionist Union (24) and try for a broad government of national unity?
This drama of political brinksmanship will play out over the next 48 hours, and for those of us who enjoy Israeli domestic politics, we are in for a fun roller coaster ride.
If Bibi can't form a government in the next 48 hours, the President of Israel is obliged to go through another round of consultations and then turn to the leader who is best indicated to form a government - in this case one would expect Buji Herzog, leader of the ZU - to try and form a government, while the former government (now, mind you, without a Foreign Minister) carries on as caretaker. Now THAT would be interesting...

Update (a few hours later - 5:10 PM EDT) - Shas has now signed its coalition agreement, so now Netanyahu is at 53. Will Naftali Bennett and his Bayit Yehudi (Jewish Home) party - the holdout - be joining soon? Or is this the perfect set-up for a one-day full-court press to get Herzog to join the government? None of the signed partners would present a particular problem for Herzog - and none of the big cabinet positions (other than Treasury) have been formally doled out. If there is going to be a play for national unity, it will happen now.