Using a crimp with a stretchy cord will eventually result in
breakage of the bracelet. Same with using any type of glue to secure
your knot. (It is my understanding that the chemicals in super glues
eat into stretch cord and make it brittle.) Stretch Magic is soooo
tempting to use for so many good reasons, alas, the one drawback it
has is that it will always break in the long run.
I know you're looking for alternatives to using a clasp, but what
about designing a clasp that looks like a bead since you already know
how to fabricate? A hidden clasp might be a bit of a challenge, but
well worth the effort if you can retail the bracelet at $450. You
could also use it as a selling point.