[John Jamieson]

That's what I believe. I was told (by real insiders) back in the 90's that the Japan Clipper was cancelled "Because it had already been done" and that we had a similar space booster plane that looked much like the B70 (both crashed, we were told).

You don't retire your best stuff like the Blackbird; or reveal the F17 and B2, unless the secrets are piling up deep.

[Saturnalia]

Actually, a XB-70 still remains intact at the Wright-Patterson Airforce Museum in Dayton, Ohio.