http://steve-yegge.blogspot.com/2007/06/rhino-on-rails.html
I just remembered about this and can't find any recent info besides Yegge calling it "a transitional thing"[1] in '08. It made a big splash after he announcement at FooCamp '07. Is it actually in use within Google? Has it or will it ever be released? Anyone know anything?
[1] http://steve-yegge.blogspot.com/2008/06/rhinos-and-tigers.html
I kind of worry that the timing for open sourcing it now isn't the greatest, since with the advent of all sorts of commonjs bits, people probably already have their own frameworks. Also, the implementation lags behind what Rails looks like now, so its a bit... weird.