Well, you can make one yourself:
Download the Hexxeh's Chromium OS build (torrent | http 1 | http 2 ).
Instructions for writing your Chromium OS image onto a USB stick for
Download Image Writer for Windows
and extract the
program. Launch the program, and
select the image (
and your USB drive letter from the
drop down box. Click "Write". The
install image will then be copied to
the drive. Once it's done, close the
program and you can then boot from the
Extract ChromeOS-Cherry.img and run
the following command in the same
directory as the file, where X is the
device name of your USB drive.
sudo dd if=ChromeOS-Cherry.img of=/dev/X bs=4M
Once the command finishes, you can
then boot from the USB drive.
Firstly, unmount the drive you want to install Chromium OS to. Place
the downloaded file onto your desktop.
Open System Profiler, click USB on the
list at the side and then select the
entry that represents your USB disk.
Now look for the BSD Name column.
Remember what is written here. In my
case, it is disk1, but in yours it may
be different. Take care here as if you
get it wrong, it could seriously mess
things up. Once you have this, open up
Terminal and type the following
tar -zxvf ChromeOS-Cherry.tar.gz
For the next command, replace X with
the name of the disk you found
earlier, ie disk1.
sudo dd if=ChromeOS-Cherry.img of=/dev/X bs=4m
This command will ask you to enter
your password (the same one you enter
when installing software for example),
type it in and press enter. This
command will take a while to run,
about 20 minutes for me, and then will
give you your shell prompt back once
it has finished. Once it has, you can
remove your USB drive and boot from it
(but not on your Mac because I'll tell
you now that won't work, yes I tried
And then, boot from USB!
NOTE: The username and password are both facepunch for this build.