GIRLS!!! and dude...
I think I may have found our elusive elastic castoff for toe up sox. Uh huh yep yep yep!!! It's called Russian Bind Off (or Icelandic, same concept actually).
It entails that you k the first st, place it back on the needle and k or p the next st through
the first st, slip those off the left needle, place the loop back on the left needle and repeat across, either purling or knitting the next stitch as it presents itself.
This makes a very nice stretchy bind off. Something us toe uppers have been looking for!!!