Hey Matthew,
It will not be that long before we ship the next version, and we will most certainly announce it here. When structure, testing and dependencies are a little more stable I would expect us to ship more often on our dev channel and update a stable channel once every few months (comparable to the normal dart sdk) - but we are not there yet, and the actual general schedule for that is not set in stone yet.
If you need to test some fix out that is a result of something that we fix there are archived builds from our master branch on the sdk bots, e.g.,
http://build.chromium.org/p/client.fletch/builders/fletch-linux-release-x64-sdk/ have download links in the individual builds for linux. I would not generally recommend these builds, since, again, we still have work in progress that may cause unstable versions there where either scripts/compiler/vm/agent is not working correctly.
Cheers,
Rico