Google has just opened up access to the development builds from the updater tools inside the Chrome browser (you could download always download dev builds from the Chrome site, or build
your own copy of Chromium...). You can
download a small tool, the Chrome Channel Chooser, to define which branch of the Chrome development tree the built-in updater uses - the slow but stable beta branch, and the fast, but risky, dev channel.
Me?
I'm going for dev. I kind of fancy the ride.