With the current code I press iso then play and can toggle without removing the eye from eyefinder ALO, with < then PLAY I toggle metering mode, once learned all those shortcut can be used without watching the menu. That's not as simple as a button switch but gives a lot more flexibility.
My idea is to put a selectable list of ml item in DriveDialog and use up/down arrrow to select what to toggle and LV button to activate it. So you can have set Expo lock before shooting and < then LV will toggle ExpoLock without leaving the eye from viewfinder
Sounds absolutely terrific and flexible, I really hope you can add this!
The only addition I'd like to suggest an on/off feedback for things that aren't visible in the viewfinder or top lcd - for example for expo lock you only recognize if it's on or off after changing something. My suggestions:
* beep for on (when having the eye to the viewfinder)
* big message on the display ("Expo Lock ON" or "WB set to xxxx").
This of course on a rebel like camera layout, for the pro wheeled camera I need suggestion eventually.
With the 60d and 6d this should also be ok, that leaves the 5dc/5d2/5d3 - in these cases the joystick should replace the directional keys.
As for the back wheel: This would be great if used for non-binary options like white balance, if you manage to add lv+back wheel for changing this you'd fix a major problem with the 6d in comparison to the 5d3 - on 5d3 you can access wb through buttons, on the 6d you have to use the menu.