1. Central Processing Unit (CPU) Bound
Minimum: 1 core per WoW instance
Recommended: 2 cores per WoW instance
This is incorrect, as the amount of cores required depends completely on the speed of that core and other factors like your target framerate.
For example: I have a quad core CPU at 2.67Ghz. When I put 1 WoW instance on 1 core then this WoW instance(rendering at 30fps fixed rate) uses only about 50% of the core's CPU time.
Adding extra cores for 1 WoW instance will very likely not make any noticable difference.

2. System Memory Bound
Minimum: 600MB to 1 GB per WoW instance
Recommended: 2 GB per WoW instance
This is inaccurate, because it completely depends on the operating system, the OS settings(cache etc.) and the WoW quality settings. All these factors influence WoW RAM usage.
A minimum doesn't require a range, because a minimum is a set limit. Settings will also differ greatly depending on whether you use the windows 'swap file' or not.

6. Network Processing Unit (NPU) Bound
Minimum: Ensure your ISP connection's upload speed >= number of WoW instances * 56Kbps upload speed
Have you actually measured WoW's network speed? One WoW instance uses about 3kByte per second (1.5 up and 1.5 down), which is far from 56kbits per second last time I measured it.
Also: a 56kbit telephone line(which you are insinuating) is absolutel not comparable to an ISDN/ADSL/cable connection with an increased speed.

Recommended: 64-bit operating system for 4+ WoW instances running at full spec.
The reason for running 64-bit is when you have a 64bit CPU and when you want to use more than 4GB of RAM. This is a quite an important detail.

A node In the Unified Modeling Language (UML) is a computational resource upon which UML artifacts may be deployed for execution. [...]
Why quote that? This is one of the pieces of information that makes the article very bloated(9 lines of text that have nothing to do with the article!) and unreadable, as it's completely irrelevant information.

3. CPU Bound:
Observation 1:
While in Outland and also in the original WoW, overclocking my 4 core setup from 2.66GHz to 3.2GHz resulted in a modest 5-10 fps increase in each of the WoW instances.
How is that relevant information? It says absolutely nothing about FPS targets, how the original FPS was, whether the FPS increase was necessary, etc. etc.

I see a lot of references and observations, but our article really misses concrete (general) conclusions to be of any value to other people. There are too many inaccuracies, gaps and errors too, in my opinion. (I just picked out a few)
Sorry to be so negative, but please don't give people general hardware advise based the observations for your specific hardware.


[edit]
Also, an upgrade from:
4x2GB DDR2 800MHz

to:

4x4GB ECC Registered DDR2 667MHz
4x2GB ECC Registered DDR2 400MHz
Memory runs at 400MHz.

... is actually a downgrade, because memory speed is quite important in 3D rendering applications.
I recall someone posting on this forum about a performance increase after upgrading their RAM(in terms of speed) to 800MHz or faster.