Jesus Vigo reviews the process to create a mutliboot USB drive used to install multiple versions of OS X.

A recovery USB drive is a separate, portable flash drive that your computer can use instead of your main hard drive to start up from. Whatever issues you're having on your system can be bypassed ...

I created a bootable USB stick using an Ubuntu 8.10 live CD and the (manual) instructions shown at this guide. This worked great. However, what I'd really like to do is create a multi-booting ...