Yesterday Dell has released modified version of Google Chrome OS, specifically build for Dell Mini computers on their employee blog.
Off course this Dell Chromium OS built by Dell engineers, customized to run specifically on Dell Mini Computers. Since this is not official product yet, according to the Dell blog post, you can download the USB key image file. All the other instructions present on their blog.
This Dell build is unsupported and you can use it on your own risk. But you have to have Dell Mini 10v net-book.
You can download the source code here. This download has 7.5 GB size.