Here is an almost identical recreation of the SAP-1 Simple As Possible microprocessor, as published in Digital Computer Electronics by Albert Malvino and Jerald Brown. While the book is out of print an "ebook" can be found fairly easily if you know where to look.
I used Labcenter Electronics' Proteus Design Suite to draw the schematic. A demo version can be downloaded from http://www.labcenter.com/index.cfm under the download tab. It can do everything except save or print, so the circuit can be simulated when opened (use the Import Legacy Design).
Unfortunately the original design uses 74LS189 16x4-bit RAM, which can only be found on eBay right now. That means it would be difficult to actually build this circuit. I am working on an updated design that uses 74HC chips and other commonly available parts. For now you can try out the classic design and see how it works for yourself.
Link to Schematic File.
Link to PDF of Schematic.