Mike,
I could turn the OD down. It would be easy. Shipping might be the hardest part.
I greatly appreciate the offer. Thank you. I'm currently in the middle of trying to figure out which option/direction I'm eventually going to go on this. The possibilities I'm kicking around are:
1) Have .125" cut off the rotor radius, make two 9/16" spacers to center the caliper and then everything just bolts together.
2) Keep looking over the winter for an 11.75" OD, .81" thick one piece rotor, make the appropriate thickness caliper spacer, and everything just bolts together.
3) Pull the 11.5" rear early C4 rotors off the '69, and mock up the setup to see if the reduced OD is still acceptable. In the event that the pads aren't sticking up higher than the OD of the rotor, then use these rotors, and use this as an excuse ro buy lighter weight two piece rotors for the '69.
Right now the '69 has the higher priority for my time, as I've got to pull the engine to replace the cam (a small chunk broke off of one of the lobes for #7 cylinder), so I've got all winter to finally make a decision on the truck brakes.