Since your question was rather vague, I've got a few questions for you:
- Let's start with your definition of Admin, Technician, or "Support Tech".
- What responsibilities do they have within the environmnet?
- Are they simply Desktop/End User Support, or do their roles expand beyond that?
- Are you lumping all support people into this same category?

Assuming you're talking about strictly Deskop / End User Support (aka. the guys who show up at your desk to fix a problem), the answer depends alot on their skill sets, the complexity of your environment, their responsibilities, level of automation, and a whole series of factors. The Help Desk Institute (http://thinkhdi.com) has a lot of information that can help. Given that you are a Windows PC shop, Microsoft has a bunch of analysis tools that can help you detirmine the complexity of the environment and suggest ways to optimize it. (Google: Microsoft Infrastructure Optimization model (IOI)).

Assuming you're talking about an entire systems support organization, I've seen IT consume up to 60% of a company's total staff (including developers, project managers, and systems analysts). Within that, I've seen up to 30% of those people to be "systems support" (Service Desk, Desktop Support, Data Center Operations, Telcom, Networking, Windows/Unix Server Support, DBAs, and various Architecture and Engineering teams).

Since you're probably looking for a swag, here's what I'd say:
For 900 seats and 9-5 operations...
3 persons answering phones
5 persons visiting desks
3 persons managing servers/storage/mail (add 2 more for networking/telcom)
3 persons managing patching and making everyone else's jobs easier (aka, engineering/projects/packaging/scripting/imaging/etc)

If you want to know where my math comes from, just ask. But it breaks down on a few assumptions of having a diverse team with varying degrees of experience and skill sets. Of course, if you have a handfull of rockstars, the numbers change, but in the end, the salaries will probably add up to being the same.

First off, I agree with the article's assessment that it is the developer's fault why UAC is required in the first part. Now, I know this is slashdot, and Micro$oft bashing is everyone's favorite past time here, but, I'm going to defend them for a moment. The reason why I say it's the developers fault is because for YEARS Microsoft has been publishing information on how application's should function to work in as "Limited Users" (aka non-Administrators), at least since the days of Windows 2000. Now, the problem is, most developers I know have never even heard of this! What is this magical mystical document I speak of? Well, it's the Microsoft Logo specifications, aka "Designed for Windows". This talks about all kinds of useful things including separation of user data from application resources; which from my experience is the primary reason why USER applications do not function as non-Administrators.

Now, I also know that Microsoft themselves haven't followed their own rules, and some applications still require administrative rights (and some stupid design decisions such as IE's Code Store Database). Combine that with the fact that they have to support an existing installation base of applications that don't follow those practices and what else can they do? Ever tell have to tell a business user that they can't use their mission critical application anymore because it doesn't work with a proper security implementation? How about telling a Grandparent that have to go buy a new version of some application that they've been using for 10 years because it doesn't work on their new PC? UAC is Microsoft's bridge to go from the old way of everyone running as Admins to the way everyone else has been saying to run, as a "Limited User". It's either that or the proliferation of the fallacy that on Windows you must run as Root.

So, UAC sucks, but can anyone actually recommend a better solution that will work for the install base Windows has? I'm not talking about the "Windows has more users than Unix/Linux/Mac", I'm say that Windows user's and developers are DUMBER than Unix/Linux/Mac users/developers. Now, don't get me wrong, there are extemes on both sides of the fence, but if we looked at percentages, the percentage of dumb users and developers on the Windows side will probably far outweigh those on the other platforms. (Queue the "well switch stupid" comments. And I will, once the industry does as well, it's all about critical mass people.)

Here's some more information on the Vista Logo requirements:
http://microsoft.mrmpslc.com/InnovateOnWindowsVist a/getstartedcert.aspx?LangType=4105

Here's the "Requirements for the Windows Vista Logo Program for Software document":
http://download.microsoft.com/download/8/e/4/8e4c9 29d-679a-4238-8c21-2dcc8ed1f35c/Windows%20Vista%20 Software%20Logo%20Spec%201.1.doc