They seriously didn't design the B-70 with an air to air refueling capability? How in the hell did that come across as a good idea at the time? Especially since that would remove most of the advantages from having B-70's on airborne alert. A mach 3 aircraft can travel 1000 nautical miles in about half an hour, meaning that practically a B-70 off the coast of Norway would be capable of reaching Moscow prior to ICBM's (with a flight time of roughly 45 minutes) arriving. However, the lack of aerial refueling kind of renders that point moot I'd imagine.
I have no found a Xb-70 documents, what so ever that issue the air refueling capability.
Given the document mentioned earlier, I'm very much leaning towards a view that the primary reason for the cancellation of the XB-70 was that, as was admitted at the time, it was an incredibly expensive aircraft, with the prototypes that were built coming in at around $700 million average cost per prototype and $1.5 billion for the whole program (assuming that figure is for 1960 dollars, that's literally $5 billion per aircraft and $12 billion for the whole program in 2017 dollars)
The B-70 had to be made of expensive Materials like light steel sandwich panel, today a common, but in 1960s very expensive aerospace stuff !
Next to that was North American unsparing with expensive and exotic materials, like 24 carat gold used in parts of A-5 Vigilante or XB-70 for it's Heat reflective property.
also would be the B-70 price higher, wenn the Pye Wacket rocket is included.
and there issue of operating cost, the B-70 is a fuel boozer because it's six General Electric YJ93 turbojet engine, making also the B-70 the LOUDEST Aircraft ever build !
Oh by the way, it expensive jet fuel JP-6 was special design for the B-70 and got also canceled after end of XB-70 program.
the High operating cost was also reason why supersonic B-58 was pulled out of service...