I've followed those instructions for my usb stick. Only diff is, I wasn't interested in putting all those distros into my stick, I just needed Ubuntu 10.04, 32 and 64-bit, so I dropped those 2 iso's ...
I just want a USB drive with an ISO folder- drop .iso files and if you boot off the USB, you get a menu to choose one of the ISOs. Bonus if it does UEFI and BIOS. Ideally, it doesn't require Windows ...