>The source code for that sets up and executes the CPUID instruction states that this gives "limited detection ability" but any clone manufacturer that returns "GenuineIntel" from this will be sued off the face of the planet.
>

There's are a couple good whitepapers on CPU identification on http://www.x86.org/ddj/ddj.htm - be warned, this is targeted at system nerds, so if you've an allergy to machine code, or will turn to stone when very non-VFPish things are flung at you, this is not a good place to go...

The specific artciles are:

November 1996
CPUID Algorithm Wars -- Part II
Robert presents a processor-detection algorithm that can obtain processor stepping information on processors that don't support the CPUID instruction.

September 1996
Detecting Intel Processors: Knowing the generation of a system CPU
How does your program know which Intel processor is the current system CPU? Robert looks at the options, including Intel's PUSHF/POPF technique.