For about two years (since AWTA 2009) I know that people at Opera Software are working on OperaWatir, but the release was scheduled as "soon" all the time. And then when I almost lost any hope, Andreas Tolf Tolfsen published a blog post saying OperaWatir is (pre)released! (One can argue is it a release or prelease, but who cares?)
The source code is available on GitHub at operasoftware/operawatir.
OperaWatir, welcome to the Watir family! :)