Creating another bureacracy to reduce bureacracy is a self-defeating endeavor. You just end up with another bureaucracy.
The US Office of Management and Budget (OMB (Executive)) and the Congressional Budget Office (CBO (Legislative)) should already be performing this work, or should pivot to doing that work when Trump is inaugurated.
To slay the beast, Government needs to be starved of headcount, budget allocations, and revenue. Reducing the size and scope of the Federal Government requires it to be crushed and asphyxiated by an anaconda of fiscal discipline.