The more I reflected on it, the more I wanted a ☠ skull key (olde-hat Dungeon Master ex-addict that I am), and while that would have been a breeze under any self respecting unix system, with tools like xmodmap and xkeycaps, I couldn't for the world figure out how to do it under Windows XP. Lots of painstakingly googling around later, I found some pages on how to hack the registry to remap the keyboard (for stuff already in the keymap, but in all the wrong places), then a working freeware KeyTweak and an even neater remapkey.exe in the Windows Server 2003 Reskit Tools, and finally something like the xkeycaps I was looking for, in MSKLC: the Microsoft Keyboard Layout Creator.
If I can only figure out how to avoid getting the "There was a problem building the keyboard file. Would you like to see warning/error information?" prompt and instead get the "The Windows Installer package was built successfully in..." message, things would be extra tremendous. Answering "Yes" at the aforementioned prompt, by the way, yields a "There was no warnings or errors." dialog. [OK]. I suppose I'll have to try it on another computer, reinstall windows or something. Business as usual.