My thinking on it could change, but based on the little bit of foreshadowing they've given us, she's the one I see most likely used. It may not be in the exact manner I laid out, as they have shown an ability to spring unexpected surprises. However, ever since JR was shot, leading the audience to think a major player may have been killed is almost SOP. Instead of wondering along the lines of who shot JR, I tend to think more along the lines of how they're going to bring a dead character back to life.
Ultimately using Starbuck for breeding purposes would be a major twist in the storyline. Another twist would be if Starbuck decided she wanted to keep any baby she might have.