Good news -- you don't have to! Thanks to Hexxeh, you can now download buildbot snapshots of the plain-vanilla Chromium OS code. In case you missed out the first time around, Hexxeh is an ambitious young dev from England who rolled his own modified version of the Chrome OS code early on called Flow. It's still available for download, too, and likely due for an update soon as well.
The Vanilla builds he's offering are unmodified compiles of the Chromium OS source. You may have seen Google's buildbot site where they churn Chromium browser builds all day long -- Hexxeh has done the same thing for Chromium OS. He's gone the extra step of putting together some PHP and CSS to present things in a more attractive way.