I'm in the same boat as you are. I have the feeling that for now, your best bet is to not upgrade OS X. Greenbytes has announced that they will release a ZEVO update for Mavericks. Hopefully they won't keep us waiting for long. I'd like to migrate to MacZFS, though, so I'm happy to see more guinea pigs helping to iron out the bugs.
I'd really like to see ZEVO contributed back to the open source community. I wonder if there's a particular amount of money they're looking for, and whether it would be worthwhile trying to fund it with a Kickstarter or Indiegogo campaign. (Maybe the developers here would not find it useful to have another ZFS port on their hands. I don't know.)