A mistcloak is a cloak made of strips of cloth sewn together. They are attached together over the shoulders and chest like a cape, and then spread out from there. A mistcoat is a duster that’s been shredded into strips.They begin a little above the waist. But remember, there’s not like an industry that makes these. Each person commissions their own, and so they vary quite widely.
Here are some quotes from the books:
Mistcloak
He pulled open the pack, then whipped out a dark gray cloak. Large and enveloping, the cloak wasn’t constructed from a single piece of cloth— rather, it was made up of hundreds of long, ribbonlike strips. They were sewn together at the shoulders and across the chest, but mostly they hung separate from one another, like overlapping streamers. Kelsier threw on the garment, its strips of cloth twisting and curling, almost like the mists themselves.
The cloth was slick and soft in Vin’s fingers, and she quickly realized what it was. She let the gray material unroll in her fingers, revealing a Mistborn cloak. Like the garment Kelsier had worn the
night before, it was tailored completely from separate, ribbonlike strips of cloth…She paused, then threw the cloak over her shoulders and tied it on. It felt . . . different. Thick and heavy on her shoulders, but light and unconstraining around her arms and legs. The ribbons were sewn together at the top, allowing her to pull it tight by the mantle if she wished. She felt . . . enveloped. Protected.
Mistcoat
He threw on his mistcoat, a long, enveloping garment like a duster with a thick collar and cuffed sleeves….The ankle- length mistcoat had been divided into strips from just above the waist, the tassels streaming behind him with a faint rustle…He took off his mistcoat, wrapping the thick material over his arm.