The XB-36 was also the only 36 with the flush cockpit (is that politically incorrect?) glazing, all others except the 'nookaler' (to quote old beady eyes) one which had a smaller, more modern style canopy area.
When the XB was built only Carswell and Andrews had ramps thick enough to support all that weight being on such a small contact area. They took it to some other Air Force base and it punched through the ramp, thats one reason they went to the 4 wheel setup...'scuse me, can I borrow every jack you have?'