...what about TUSSAH silk caps?
Maggie pulled out an example of a tussah silk cap at my Sensuous Silk Spinning class last week, and omg. This thing is crazy. Copy of National Geographic next to it for scale.
Um, yeah. Why would you even need to spin this? You could just wear it around like a shawl! It's folded in this pic, too...you can separate the layers for a true bell shape. According to Maggie, tussah silk caps used to be available to handspinners, but she hasn't seen one for sale for about 20 years now.
For all of you non-handspinners, a bombyx silk cap or hankie is much smaller than this...usually about the size of that National Geographic there. Bombyx silk caps/hankies are still obtainable, and can be a lot of fun to spin. Just don't expect a smooth yarn from them...the resulting yarn will have some bumps and noily bits. That's just the nature of the beast.