It's no wonder that there are a pile of spare RJs:
Global Hawk RQ-4B
"Another payload scheduled to be installed on the Global Hawk is the Airborne Signals Intelligence Program (ASIP) SIGINT payload, capable of monitoring electronic signals up to 500 km away. ASIP will augment the sensor suite used on previous aircraft. The US Air Force plans to field 26 Block 30 aircraft which will share the same platform of Block 20 and 40 but will be equipped with the ASIP systems instead of the standard EO/SAR payload. These aircraft will become operational by 2012 augmenting the units currently operating by the 9th Recce wing at BealE AFB."
So why don't we take a leaf out of their book and leapfrog the next airframe straight to a UAV platform that has longer endurance, greater range, less risk (to the highly qualified and experienced operators/analysts) and is available now?