Along these lines, I've used burlap for outside purposes, and it weathers great...yes, it does degrade a bit, but that all adds to the effect.

Thud, my experience has been that pool noodles (piping insulation) are great for arms and perhaps skinny legs...but, as fabric drapes, the effect for a hunched back becomes difficult...each bit of piping insulation becomes noticeable, and it looses the "realism"...

Something I've had good luck with is chicken wire and soft foam...the chicken wire gives a continuous support, and the foam gives a smooth, rounded look, which can be modified to look a little lumpy, like shoulder blades or whatever.

Even without the foam, I think the chicken wire (or any kind of mesh you can bend and shape) may give the look you want (and the framework underneath can be and look like anything...it's all covered by the prop anyway).

__________________
Hell is an eternity of getting up at 4am to nothing but decaf coffee...
- Professor Ashfield

Ugly Joe's Photo Bucket