For people that use alternative keyboard layouts it is often difficult to make sure you are always using the right layout.
If you go to a new computer you need to setup your keyboard layout but sometimes remote consoles (vnc or java based) don't map keys properly and you still find yourself typing in QWERTY. There needs to be an easy way to switch the layout so you can switch the layout on the fly.
There are other hardware mappable keyboards but they are often very expensive or not ergonomic/mechanical.
This project is an attempt to build a USB module that can remap your existing keyboard without any software.
A main benefit would be the layout you want would then work even when a device doesn't support the keyboard layout you want (BIOS, appliance, etc.)
What about an in between PS/2 or USB dongle type device that allows switching from either keyboard to either character mapping? E.g. if I have a qwerty keyboard, I set the dongle to be "from-qwerty to-dvorak".
This way I could switch say a das keyboard without modification to the keyboard itself.
Edit: just found this - http://www.keyghost.com/qido/
I see areas of improvement for a device like that.