Towards the event of the Google Chrome Event two nights ago, the VP of Product Management at Google Sundar Pichai, confirmed that Samsung will be the first one to bring a Chrome OS notebook to the market.
Google also confirmed that it would not sell the device directly à la Nexus One but instead depend on partners like Samsung and Acer to do the job of building and marketing them.
When asked about the possibility of seeing a Chrome OS tablet, Google said that they weren't planning any, adding that they were taking one step at a time.
Promisingly though, they didn't say that they would NOT launch a Chrome-OS tablet and in theory, there's nothing that would prevent Chrome OS to turn up on a tablet (or Android OS to turn up on a Chrome Notebook).
Just as a reminder, at the beginning of the year, designers at Chromium published concepts drawings of how a Chrome OS UI might look on a tablet and explored possibilities. You can find more about these here.