I got really excited about this, thinking it was a Rails-style front-end framework. It's still really cool as a server-side framework, but I'm totally hankering

I got really excited about this, thinking it was a Rails-style front-end framework. It's still really cool as a server-side framework, but I'm totally hankering for a full Rails stack in the browser. I've used Backbone and played with Spine - I just can't help but feel as though they could go all the way. I wonder whether that's viable?