local storage vs cache

Hi,
I've been looking at why people use dom local 
storage(http://hacks.mozilla.org/2012/03/there-is-no-simple-solution-for-local-storage/ 
has some good discussion). A lot of use seems to come from the fact that 
developers don't trust the network cache.

Perhaps we could provide some apis to
* group items(this would also be a big win for disk locality)
* prioritize cache items
* query if an item is in cache + ability to request items out of cache 
without a network request(even if headers are expired)
* evict an item
* place an item in cache(ie a generated image)
* evict an item from cache

Here is post to start thinking about this:
http://www.garfieldtech.com/blog/caching-tng

I know historically we were reluctant to expose detailed cache info to 
the web, perhaps it's time to reconsider some aspects of that?

The nice thing about the disk cache is that it has expiry logic, is 
supposed to efficiently cache large blobs(something that 
indexeddb/LS[databases in general] struggle at).

Btw, it turns out indexeddb isn't a good successor to LS in current form 
because it's slow, requires a prompt, doesn't have a good data-cleanup 
story.

Taras

ps. This isn't a concrete feature request, just something to consider 
while we look at how to evolve the network cache.