I always wanted to create my own 6502 made out of TTL ICs. I soon found out that it was nearly impossible if you wanted to create a cycle exact one: you needed at least EPROMs to handle the instruction decoder.
To make a very long story short, I created a TTL 6502 only using 74xx ICs and six 29F020 FlashRAMs. But it is a simulator, it is way of being cycle exact. For example: in my original (what I think) cycle exact design, the stack pointer and program counter are handled by 74LS191s, 4-bit loadable up/down counters. In this mini design it is done by the instruction decoder and the ALU. The momentary value of the program counter is read from some internal RAM, is incremented before the next step, stored in the registers towards the address bus and stored in RAM again.

The site for this project: http://www.baltissen.org/newhtm/OnePCB.htm. It is not 100% up to date but good enough to get an idea.

The schematic: http://www.baltissen.org/images/6502miniTTL-sch.png

A picture of the card: http://www.baltissen.org/images/6502miniTTL.JPG

The main work has still to be finished yet: writing a program that fills the FlashRAMs with data for the instruction decoder and ALU.

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