Have you looked at Blogs Organizer? it will remotely post to your existing WP blogs and you can schedule posts too, all from one admin location. The posts aren't saved as drafts, they are just posted when the schedule says so. Do you need that specifically?

BO also lets you get more out of it by creating blogs with its system, and the bonus is that its secure and only updates maybe once a year, unlike WP blog software!!! I use it for all my blogs and love it!