I've got great news then: you can make the jump to RoR today! :)
This news isn't about Rails implementing its own background queue, but rather creating a unified API for interacting with background queuing systems; of which there are many. Resque (crafted at GitHub [1]) is probably the most popular: https://github.com/defunkt/resque.
I've used it in production for a few different projects and highly recommend it (both the PHP and Ruby versions).