Actually most of the popular minicomputers of the 70s (DEC, HP, DG, etc) were built with lots of pretty basic gates, FFs and registers. The most complex chips used were typically 74(X)181s for the ALU and LSI UART chip for serial communications. Layout was usually pretty straight forward for all the data paths. It was the instruction decode area that was usually a mess
Hmm... well thanks for your reply guys. I'll probably have to have a long think about it.
Yes, but you're talking about very very fast computers, that have all kinds of specialized circuitry. It wouldn't be anywhere near that hard to make a computer if it only had, say, 2 bytes of memory.
Take a look at this wikipedia 'home-made' computer made from 7400s:
Yes, but it's pretty complicated and not capable of doing anything - it's not a question of speed, it's a question of capability - you can build a computer using relays (and the first ones were like that), and although obviously slow they were pretty capable.