One wonders why, given that we are getting some Gucci new tankers, we didn't just buy some A330 airframes and add the relevant systems? A330 has high altitude, long endurance/range, plenty of available conditioning and electrical generation, space, ability to carry plenty of GSE/people when deploying, space, commonality with Voyager etc. Too late now of course, but just a thought.
One wonders how much an Airbus would've cost to spec up to 'RJ standard'. A sight more than incorporating ours with the USAF's, on the known entity that is the Boeing, I should think.