Looking at many of the secure key storage and "loaning" systems, I found that there were tons of very expensive, highly complex products that we didn't need. Many were electronic, and had tons of "features" that seemed to make them less versatile. I also found a very simple device, which fit our price target (cheap!) that filled all of the requirements. It's a little plastic box that snaps closed. It's not tamper-proof, it's tamper-evident. The product's web page talks a lot about keys being managed for apartments and the like, but it is also mentions things like passwords, and the almighty emergency petty cash stash.
I ordered some of these, and tested them for tamperability. They aren't hard to break, but I have yet to figure out how one can open them without showing evidence of such. I stopped trying, because I think it fits my needs perfectly.
Here's how they work:
1. You put something in the little plastic containment area.
2. You snap the cover on (make sure you have what you want in there, there's no going back)
3. You label it, or sign it, or whatever (it has an inkable surface)
4. If someone needs it, they they perform sweet glorious destruction on it (i.e. step on it)
5. They retrieve the password, and screw up the server
6. You return from vacation. You fix the server, yell at everybody, and change the password.
7. Grab and use another plastic doohickey for the new password.
Seriously, though, I could have used one of these while in Brattleboro, VT. Instead, when I got back to cell phone world, I had dozens of messages on my machine. Yes, there was someone covering for me, but they were unavailable for whatever reason (we operate in remote areas with limited cell service).
What I think is so perfect about these things is the simplicity. Frills are a minimum, though you can apparently get attractive metal or wood cabinets for them, and label tags, and all that stuff. Still cheap, but we only need a couple of dozen. They seem to do a bit of business with Landlords who need the ability to access an apartment with accountability. But I am impressed with how well they adapt to the technical world of having very few people with admin access. You can find these doohickeys on http://keysure.net/ for $6.60. Much less than spending literally thousands on a crazy contraption that will surely require more tech support when someone needs to use it. I have contacted the manufacturer, and recommended they contact ThinkGeek, as I think a lot of other admins would like to take a vacation as well.