I frequently switch between a terminal and a web browser/kindle while working on the device with a bluetooth keyboard. The method I used on the stock 3.2 (with TouchWiz) ROM:
press the home key on the keyboard
down-arrow, which selects the top-left icon on the current home screen (generally the terminal)
arrow to the app I want
press enter on the keyboard.
CM9 foils this method by putting the focus on the search bar and voice search stuff at the top of the homescreen; I can't arrow-down from there to the icons I'm interested in. (EDIT: if I remove the search bar, focus still does not go to the app shortcuts.)
I use both the Logitech Tablet Keyboard for Android 3.0 and Samsung's own keyboard/dock. At least on the logitech, holding the home key has only the effect of delaying the 'go to home' action. It has Fn-keys for mail, web, calendar, music. I really only need a quick method for three apps.
What are my options for task switching on CM9, using a keyboard?
Misfeatures of a method:
Tasks are presented with changing order. This means that I have to examine the screen to make a choice - it foils muscle memory.
Tasks are linearly presented. This wastes three of my arrow keys, and - already, with just three tasks - creates an artificial distance between the first and the third task. I'd like to create my own sense of distance between tasks - as I did in the 3.2 method above, by having terminal first, kindle to its right, the browser just below it, and then secondary apps arranged elsewhere.
Every recent task is presented. I generally don't want to switch back to Settings - or to the app I just tested, am now rebuilding, and will launch as part of the installation process.