To go with the Dupioni Silk dress and wrap I made, I augmented an evening bag. I was very lucky to find a old black second-hand evening bag with very minor staining on the outside and a strong clasp and clean inside.
I took a piece of the silk and tucked the edges under. Then I slip stitched it around the edges. No other work was needed.
The fabric shown is Frosted Pine 54″ Dupioni – available from SilkBaron.com. I highly recommend their service and their silks.