Keep nwa.com Club in mind as it would take you halfway there. For $35 you get a 2K mile sign up bonus, plus a certificate for 3K miles off an award certificate booking. Membership is closed at the moment but will probably open up sometime not too far off. You can sign up for e-mail notification when they resume accepting memberships at
http://www.nwa.com/club/index.html

MCI is also running a 3K mile special for long distance. But keep an eye out for better offers. I'm on one for 5K that I signed up for not too long ago.