I have the need to cache an immense amount of images and data locally.  No, I cannot use AIR.  Since I cannot depend on the browser cache, I'm currently using a modified version of Ely's SuperImage, and plan on saving the images as compressed ByteArray's in local SharedObjects.  We have no qualms asking the user to up the settings the SharedObject settings panel, unlimited even.  For data, we're doing the same thing.  While I don't mind writing my own, this project is time intensive, so was curious if someone has already built a local caching engine for ActionScript data objects and images.