Using a microcontroller as a microcode sequencer?
I don't think it would be cheating at all. That's what microcontrollers were originally designed for, after all. Nowadays, we treat microcontrollers as fully programmable computers (small ones), but they were originally built as microprogram controllers. If you use one that way, you can build all the registers of your system (the "architecture") in the conventional way, with flip-flops. The microcontroller then acts as literally the "controller" of the system, switching over multiplexers and enabling the clock input to the flip-flops.

I have a really good book on this, but it's at the office right now. The main theme is to build a PDP-8 using registers and microcode. I'll look up the title and author tomorrow.

UPDATE: The book is "The Art of Digital Design", by David Winkel and Franklin  Prosser. ISBN 0-13-046607-7. Published by Prentice-Hall, 1980.