After seeing it discussed on Ravelry, I was inspired by Rachel Henri’s Stretchy Cast On (see: https://www.youtube.com/watch?v=xB5cnwVwnwQ&t=21s ) which is listed on her web page (see: https://rachelhenri.com/en/home/ ).
This is great, so I went looking for a matching Bind Off.
My best result (her cast on is at the bottom and my bind off is at the top):
To do the bind off, I did a reverse pass and then did the last row with hybrid traditional/tunisian stitches. All this is in gold yarn above.
First I pulled a loop through the front vertical bars of the previous stitch and the next one:
This picture is simplified. There should still be a loop on the hook, left over from the previous stitch.
Next I added a chain to the top of the loop I just pulled.
Then I pulled the final loop through both the loop I just created and the loop on the previous stitch. These are the two (2) loops shown on the hook.
One bit of trickiness: I’ve used a J-10 hook with worsted weight yarn here. I had to use an Extended Simple Stitch for the body of the work or it curled pretty severely. Another option would be to use a larger hook for the body of the work and use a smaller hook for both the cast on and the bind off.
Hope you try it and perhaps come up with something better!