I installed Ubuntu 7.10 SE (my remastered Ubuntu) on a Transcend 8GB Class 6 SDHC card with a no hard drive desktop computer as usual. My desktop is using mobile rack and it is very easy to remove the hard drive. Make sure to use ext2 and without creating swap partition.

After the installation, I deleted the xorg.conf at /etc/X11 to make the SDHC capable to run on every computer. You can delete the file after the reboot from the SDHC on the no hard drive desktop.