*** UPDATE 12/19/2012 ***
This Thing has been restored. Thank you, Thingiverse, and please do your best to avoid falling too far down the slippery slope that all censors must stand on.
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The following was initially typed in response to some of the inflammatory comments posted below [edit: flamebait posts removed, thanks!]. My commentary grew out of control as I realized this isn't something I've talked with anyone in depth about, ever. I understand that censorship is bad and rightfully makes people angry, but please try and stay civil. The people who blame tools for the deeds of evil people may be frightfully mislead, but their need to make a change comes from a good place. They've been hoodwinked by some very bad people that will use terrible acts to push their own agendas.
Anyway, here's my rambling words. They come from a person that is, by nature, an engineer, a maker, a fixer. Five years ago I was briefly exposed to a frightening break in society. I've spent too much time since then trying to figure out a way to make that break go away. To engineer a solution. To fix the problem.

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My issue with people crying "gun control!" is that they respond from emotion, but inadvertently seek to create more victims in their zeal to DO SOMETHING RIGHT NOW to stop these terrible things from happening... Unfortunately, I don't just say this as an armchair quarterback with no experience. Five years ago there was mass shooting at the NIU campus in DeKalb IL. That madman killed 5 people, and he shot many more... yet gun control laws worked as well on that day as they ever could work. There were at least a hundred people in that room, and the killer had every intention of being the last one alive. The first NIU police officer was in the room within a minute of the killer's first shot, and everything was over just like that. There were only two people holding guns in that room - the criminal, and the police officer... and the killer shot himself in the head as soon as he saw the officer's gun. No police force on the planet could ever be more effective as the NIU police were that day.

Now, ask yourself what could have saved every single person in that room. More gun control?

Psychos like this *need* defenseless targets. Let's not give them more. If it was legal in IL, I'd donate money and time to train and CCW license every teacher at every school my child ever attends. I don't care if those teachers choose to purchase a firearm afterward; the possibility that the teachers might be armed and prepared - and that psycho killers at large would be aware of this fact - is enough for me.
I'm a former Boy Scout, and while adult me can't support them for their hate-agenda, they did teach a younger me something very important: Always Be Prepared. So let's talk about preparation.
There has not been a single child fatality in a school fire for than 50 years. There have been plenty of fires - on average something like 150 per year in the US. The reason we don't have fatalities in these fires isn't because fire isn't dangerous - home fires have terrible statistics that should prove to anyone the dangers of fire. Nor is it because there are no bad guys - according to FEMA between 60% and 70% of school fires are cases of arson. The bad guys also aren't hampered by a lack of access to flammables... Instead, schools are safe from fire because we are prepared for the possibility - schools have drills, fire extinguishers, sprinklers, alarm switches everywhere, and even more drills. Everyone - staff and student - is prepared and knows what to do, and there is mandated equipment on site to begin saving lives *before* rescue professionals arrive on the scene. I don't want to think about how differently the statistics would be if, instead, we chose to try and regulate matches and lighters and gasoline, or anything else a bad guy might try to use to start a fire. Preparedness works.

From someone that never wanted to see first hand brains, blood, or too-still faces, and never wants to ever again... rest assured, I have thought about this a lot more than you.

Here are the answers I have been able to come up with:
1: Strict gun control. This will never work. Illinois is the only state that can 100% guarantee every law abiding citizen is unarmed... Bad guys don't care. Mexico has some of the strictest gun laws on the planet, and open fighting in the streets.
2. Visible police presence at every entrance to every building. I'm for this. It'd work both as a deterrent and as a quick(er) emergency response. We'd need to find a huge amount of money to balance that budget sheet, though. Impossible.
3. The mental health system in this country, as with the overall health care system, is entirely broken. I'm not able to imagine a solution, but I know corporate profit driven-private healthcare isn't it. Try breaking a bone in Costa Rica. You'll be set, in a cast, and on your way to the pharmacy before a US facility will even process your insurance... Because Costa Rica won't ask you for your insurance. They've prioritized health care and it shows. This will never happen in the US. There's too much money in healthcare and too many lobbyists lying to people about national health care systems in other countries.
4. Concealed carry for citizens. Steven Kazmierczak stopped killing the very moment he realized he wasn't the only person in the building holding a gun. Make sure that some non-zero percentage of the population is armed, trained, and proven competent with that responsibility and you WILL stop some of these these crimes from happening, and stop or slow down others before they've done the maximum amount of harm they could accomplish.

That's the only way I can think of that we could have saved 5 people that died that day... And that was a best-case-scenario for police response. Any better requires the fortuitous and unplanned presence of an officer, like we saw in the Hobbit attempted mass shooting recently.
Five dead = best possible outcome? Something definitely needs to change, and creating more defenseless victims isn't the right way to go.