I’m still working on my first Whitney so I have limited experience, having only made a (fiber fill) prototype. Having done that much, though, I am not so sure that adding a hood after the fact would be an easy task.
If you were willing to take apart the collar, you could make a hood and them sew it into the collar. You could also install snaps or velcro strips on the back of the collar and make a removable version. Seems like I remember seeing some kind of velcro with an adhesive backing too.
However accessing the collar seems like it could be a messy project. It seems like it would be hard to access since it was both sewn and stabilized. Since the side seam is the finishing seam, I think you would have to take that apart if you wanted to cleanly get at the collar stitches. And it’s a French seam so double the stitches to undo.
But another option might be to make a standalone hood with long sides and back that would tuck inside the jacket. Might look funny around town but would be super functional on the trail. It could double as a hood for a quilt system and you could always leave it behind if not needed. You could make something like ZPacks hood:
http://www.zpacks.com/accessories/gooosehood.shtml
But the best option might be to just make another Whitney! That would be my choice. ;)
Nick
