> I wonder if more than one Natami CPU daughtercard was assembled?
Assuming you refer to "MC68060FE133" CPU boards here (there are others, also with full 68060RC chips), click the second last link I provided* and your question should be answered.
> alternative socketed 68060 chips are still available to purchase for their designs
Yes, but none of them claims to be able to run reliably at 133 MHz. Motorola/Freescale have only been guaranteeing clock speeds of up to 75 MHz for EC and LC parts and 60 MHz for full parts. If a hobbyist thinks that even the (about) 100 MHz that a full 68060 Rev.6 is overclockable to is not enough for his project he might be inclined to try a part that claims to run reliably at 133 MHz without overclocking.
