I'd really like to design and build a PDP-8 clone,
since the real
ones command such hefty prices on eBay. I've mostly given up on
getting my own 8/F or 8/M.
See this book for a discussion of the design of a TTL PDP-8 :
"The art of Digital Design"
(An introduction to Top-Down Design)
second edition
Franklin P. Prosser
David E. Winkel
ISBN 0-13-046673-5
-- hbp