Intels Pentium and PPro manuals are on their web site. They seem to be
complete enough for your task.
What you are describing by the way is how things like the Executor Mac
emulator do to get fast Mac emulation on a Linux box. Before you leap boldly
into action remember some little 'catches'
1. You have to play with mmap and mprotect as well since there are
side effects you have to emulate (page table dirty bits for example), and
some memory writes eg to the page tables affect the emulator however they
are done by the process you are running.
2. Self modifying code
3. Even worse, code that looks at itself to see if it needs to self
modify this time.
It is doable Im sure but it is also a big job.
Alan