Geraint Wright asked if I could build a quick rig for a sparrow animation (model would be supplied).
This is where it is atm. (still alot of work to go into it) but alot of the base ideas are there.
The separation of the feathers was far simpler than I though actually, using a couple of curves and the very useful pointOnCurveInfo nodes (same nodes used in motionpaths but without the extra crap), then just a basic heirachy of dependencies of controllers and aim constraints (the feather bending is hideous but was only quickly thrown together, needs more thought behind it so expect that to change).
One issue (kinda solved, looking into better solutions) was due to the aim constraint, feathers wouldn't react accordingly to folding or certain positions, especially when pulled about a fair bit. Simple solution was to declare the aims up object as another controller (well, one for each segment).
Alot of automation (of course each with manual overrides and on/off blending) will be needed to get a smoother transition and to 'hide' any smaller issues, included with a smart system to fold the wing (some scripting required).
The animation it'll be used in you wont really see much of the detail but I'd rather put the work in now if any shots/ideas for closer cuts are thrown in...