It ain't Piedmont. First they can't buy anything on their own. Second US Airways is cutting capacity down. Third, Piedmont is scoped out of them. Fourth, getting Piedmont Q400 would make too much sense.
(I don't think it's Colgan, when I worked there they were going to option 15 with another 15 waiting in the wings. Here at ANA we're supposed to be getting Nextgens sometime in the future but I hadn't heard anything beyond that.