Bump.
Sorry, it's appears that you can only unpack files that are in your add-ons folder. The rest do not have names stored for them therefore there is no way to detect what the file's format is (PNG, BLB, DTS, etc). You could detect the type by reading the data for the file and going from there but you still wouldn't have any idea what the name of the file is. Therefore you would have to go through 1000s (depending on your cache.db size) of files named like "551a68a20aca41bc0dd97768d389b ad249029983" so in the end you still wouldn't have a clue which one is the file you're looking for.