I've officially released weeds a rails plugin to make your application SproutCore compatible out of the box. SproutCore is rapidly changing so there have been major updates already. I'm keeping up with edge SproutCore so that Rails developers won't need to alter their applications to take advantage of improvements.
So, give it a shot:
script/plugin install git://github.com/trek/weeds.git
and let me know if you run into any problems by posting a ticket on lighthouse