Unfortunately, it's not this simple;

The disk portion of the upgrade file just un-gzips an image over the entire partition. To make an upgrade file with the player and ftp/telnet/etc on it would require you to be also distributing the empeg player binaries - something which we really don't want to get into as (apart from legal complications) it is a support nightmare - and people could even make malicious upgrade files which toasted your music partition, which would then be applied by people who really shouldn't be playing with a loaded bash prompt ;)

Currently, it's much safer to do the tarball thing.

Hugo