"This rewrites all files for /zap/j/anything-anynumber.js to /zap/j/anything.js and /zap/c/anything-anynumber.css to /zap/c/anything.css"
Why post a file called "foo-12930.css" and show it to browsers at "foo.css"? The opposite is better - keep updating foo.css (and use version control), but show it to users as "foo.css?some-timestamp". This is what Rails does. If your server is configured to tell browsers to cache CSS files for a year, they will request the file once, then continue to use the cached version until you update the file. Then they'll see that it has a new timestamp and get the new version.
but with no attrition.