casearis

A lot of distro's are available with supported persistence built in, puppy linux, porteus, slackware, slitaz, and yes also Ubuntu and Debian. Through past experience Puppy has it made, runs...

Not sure if persistence will be added to etch.. for ubuntu distro's, unetbootin and liveusb cover that.. however, needs to be fat32/16 filesystem. Try multiboot-usb, good for testing live iso's....