Some of the ideas are already present in Magnet links (http://en.wikipedia.org/wiki/Magnet_URI_scheme).
This would avoid the inefficient situation we have at present, where the same jQuery script is fragmented across dozens of CDNs, causing a new request each time even when previous instances are already cached by the browser.
You almost never point directly to a dependency as a standalone file. Doing so would mean 15-30 requests per webapp and since browsers only accepts 5-6 parallel requests, it would slow down the page considerably.