Amazing find there, thanks! Who would have thought one Minecraft world was so huge.
It would be neat, but honestly the complexity of a modern CPU is not something that any individual would be able to recreate in a life time if they were building it piece-by-piece. I imagine that's true for any CPU capable of running recent Ubuntu releases or even something light like, I dunno, Puppy.
I'll settle for OS/9.
Actually, the complexity of a modern CPU is mainly in making things run fast. Building an in-order, no-cache, single-issue ARM capable of running uClinux doesn't seem all that difficult. The cycle time would be horrible though. You might not live long enough to watch it boot.
That's kind of what I was getting at with "capable of running."