I would imagine that unless you had extenuating circumstances (ie your wife was dying of cancer), then I don't see the AF letting you out of a commitment, especially if it's to fill a 'must fill' deployment. It's funny you ask this because I personally know a good dude (prior WO) who had taken the old long term bonus that took him past 20 YAS and when he tried to drop retirement paperwork at 20 and pay back/not collect his unearned portion of the bonus, the AF said no and instead...he got hit with a 365 to the CAOC. Grant it, this is anecdotal, but I think this recent example can give you an idea of where the AF stands on this issue.
I can't believe I'm quoting Chang right now, but he was correct when he said that the $25K/yr bonus (even the large bonus now) is a "drop in the bucket" and worth it to the AF to not have to worry about someone dropping papers at some random time. For the younger guys on here, take heed: If you're not fairly confident that you want to stay in for a bonus commitment, then don't take the bonus.
Sorry man. Good luck with the deployment if it happens.