Heroku Rails 3 all.css / all.js dynamic generation?

I'm currently wrestling with a lot of all.js / all.css missing hits on a rails 2 upgraded to 3 app on Heroku. I'd prefer not to have a dozen or so stylesheet links per request, and also don't want to statically bundle -> s3 the files as part of the deploy.

This seems like a familiar problem, preparing some content specific to a url and sending it back to the browser.

Rather than using an external bundling app as part of a deploy script etc, has anyone considered having rails generate these files on-the-fly and use varnish to cache them (since it's cleared on redeploy, which is when the css/js files would change)?

My question is whether this has been done already & I just开发者_如何学运维 failed to google it, or if it sounds like a dumb idea, why?

Even better: Rails 3.1 asset pipeline does exactly this, and Heroku handles precompilation and caching for you.