Those teachers who apply and earn their NBCT are not the ones who are likely to leave the profession, they are committed teachers.  Paying them more bonuses will not likely have an effect on whether or not they will stay.  
The DOE must first attract and then support new teachers.   Higher starting pay to draw the bright to teaching,  a pay scale that rewards teachers to stay in the profession, and support for those beginning teachers in the form of mentoring and/or cohort support groups would go a long way in attracting and retaining teachers.
I highly doubt those considering teaching,  just entering the profession, or contemplating leaving the profession, think to themselves "Hey, I wish the NBCT bonus was higher!" 
Lastly, the DOE needs to create more "pre-teacher" academies in those areas hard to staff.  Where those who live in those areas consider teaching in those hard to staff locations.
Congratulation on earning your NBCT!