Andy Skelton posted a proposal for a mechanism by which a web server could send related objects to a resource in response to a single request. It’s quite an interesting idea, although I’m not sure how much we could gain given that most clients today do HTTP pipelining.
It could reduce loads on the server, but I’m not sure either. Most static content is served very efficiently on the server using the sendfile (2) system call. By mixing static content with dynamic (the HTML which has to know what its embedded objects are), it may be difficult to implement efficiently.
That said, it could have some merits, and a more in-depth analysis would be needed and I’d be interested to see how it pans out.