I think the Kurds will support the sunnis. They gave refuge to Vice-President Tariq al-Hashemi, a sunni. Sunni Anbar province wants to be more independent and when civil war starts they might go for total independence and the kurds propably will follow and will try to seize the oil fields.
Question is, what will Iran do? Will they send "peacekeepers" to save Maliki's government, or wil they jusy send money, arms and fighters to the militias?
Do not forget that Iran is losing Syria, so Iraq can come in handy. On the other hand Saudi Arabia might also be eager to "re-sunni" Iraq and will surely help the sunnis.
And the US? It's election year so Obama might be more agressive.
Anyway, 2012 will give us the answer.