You should see what GE do on their very latest, very greatest MRI scanners. To turn things on and off they have a box next to the feature. You type "1" for on, "0" for off. If you deviate (type 0.5) you get a message saying that only 1 or 0 are valid. As it now 2013 I wish they would remove their command line stuff from the UI.
Unbelievable! Do you have a picture or something of this? I used to work on similar interfaces for a competing company and this stuff fascinates me :)
Message me your email and ill fire it through. A developer at work looked like he would cry when I showed him!
No they're not. Checkboxes are fine for boolean on/offs. But from the OP: "often the choice is not between turning a specific feature on or off, but between two different view, modes or whatever."
Here i think the Quija sliders really are a smart, intuitive solution