OpenSolaris in a 4GB Thumb Drive, then Ubuntu
Usbdump integrated into the LiveCD. You can now boot from the CD pop in a USB stick and execute usbdump in a terminal to get BeleniX on USB.
Although it works, the /usr partition is mounted as read only and therefore I cannot do any package installation.
Anyway, the 4GB thumb moves on to Ubuntu 6.10. Why not the latest 7.04 'cos most of the people complained about having problem with this version. This article from Pendrivelinux.com has a very detailed step-by-step guide.
I partitioned 2GB FAT16 for the OS, and 2GB ext2 for my /opt. It is possible to do "apt-get install" to install packages.
What's next for my 4GB? I have no idea.