From what I understand, there will be 30 Q400s on property after these deliveries. Colgan has options for 30 additional Q400s (60 total). Of those, 15 will be delivered starting in 2013ish. There are no plans for the other 15 right now.

Mesaba will be losing their 26 Saabs starting in January. The leases are owned by Delta so Pinnacle/Colgan/Mesaba would have to take over the leases and find flying for them.