After a long ago requested but delayed briefing precipitated by Jed Babbin's article Too Big, Too Heavy a member of our team was given information on the possible construction cost related with purchasing the much larger KC-30.
During the brief she was provided Google Earth satellite imagery as visual evidence to show the many problems that will be associated with replacing the KC-135 with the much larger KC-30.
As you can see from the photos, unlike the KC-767, the KC-30 footprint does not allow space for taxiing, and precludes parking on many pads. In many places the KC-30 nose is consistently beyond the pad cement.
It should also be remembered that in addition to the size/spacing issue, there are many problems a heavier aircraft presents the classified Pavement Classification Number (PCN) or strength rating of the runway, taxiways or airport ramps. Some of these ramps and taxiways may not even be able to support a heavier tanker.
If dear departed Johnnie Cochran were around to argue the case before the GAO we think he would have said a little something like this, "If the tanker doesn't fit, you must the contract quit."
In the GAO case at least, he would be right.