Just a suggestion: along with the win bonus, there could also be a subtraction from those who allowed the win. A percent taken from all survivors would be an incentive to draw.
e.g. France wins with 18 and gets plus the 15 win bonus for 33. Before this happened, Turkey had the decision to either stalemate or let France win to stab Russia for some extra SC's before the game ends. Turkey isn't sure how his stab will turn out. He could get anywhere between three and five supply centers before France takes over his three SC's in Italy.
If Turkey has 10 Supply Centers before he stabs Russia and there is a 10% deduction from your points for a survive, then:
At 10, he will get 9

At 11, he will get 9.9

At 12, he will get 10.8

At 13, he will get 11.7

etc...
Obviously, he will lose out on points if he only takes three or four supply centers from Russia (while losing his three to France). Meanwhile, if his stab is succesful and he gets five or more from Russia, he'll get more points.
Just a suggestion. It might give it too much of a WTA feel than you're going for. But it does provide incentives to both stab and stalemate.