I used rayon batiks to piece a jacket. I chose a simple design because I knew that the rayons tend to shift on you. I didn't want to put an interfacing on the back because I wanted to preserve the hand of the rayon. It worked well.
Rayons do tend to react weirdly when washed. Some are fine and some shrink or get way too soft and flimsy so I would make sure the fabrics were washed before using.