Yeah, I sort of feel like this is safest at a relatively simple scale where the efficiency gains also stand to be the smallest. Although I heart Ruby, personally, I'd be more interested to see someone nail the deep javascript stack with quality. Something like Rhino on Rails on the server, javascript/AJAX client/server, CouchDB w/ javascript views for the DB and AIR for javascript/AJAX desktop apps and widgets. Seems like with JSON around, that could be elegant and efficient at larger scales, rather than generating code from one language to another for some pieces.
