> Or you might imagine a chip that has an FPGA on the side (I expected Intel would ship this after acquiring Altera, but it never happened).

They did: https://www.anandtech.com/show/12773/intel-shows-xeon-scalab...

But I get the sense this part was aimed at a few very specific customers. It required some PCB-level power delivery changes, so you couldn't even drop it into a standard server motherboard.