I did a search and found references to internal storage related to the Galaxy, but possibly it's been addressed in other places. Sorry in advance if that is the case.
But I am on a HTC Incredible, and it would be awesome if I could set the cache location to internal storage (/emmc). I don't use the internal storage for much else, and would love to just crank the cache size up to 4GB (which I also can't do... it's 2GB or 5GB).