Funny story: I got a CR-48, apparently thanks to a coworker's friend who passed along the sign-up page about 2 minutes after they popped up a QR code for it.
No idea how large the beta actually is, but if you have questions, ask away and I'll try to find the answers. I've barely been on the thing long enough to post this though, so some first impressions from a very brief time on it:
1) It's too heavy. My Macbook Air weighs a little bit less, and despite the screen dimensions my Air is only about 1" wider (and slightly thinner).
2) Maybe I'm just spoiled by Magsafe connectors, but the power connector feels cheap and doesn't connect too well.
3) The arrow key layout is weird. Also, I just noticed, but there don't seem to be enough editing shortcuts -- you can jump by word but there's no beginning/end-of-line. (The combination you expect to do that is forward/back in the browser.)
4) It's Google Chrome. Like, really, you don't quite understand until you start it up. But all the settings you can change are accessed via the Chrome Wrench menu, and while there are some additions it basically looks the same as a full-screen browser window.
5) There aren't quite enough feedback indicators yet. It looks like there are 16 levels of brightness, but there's no indicator telling you where you are when you change it. You just push the buttons and see if they work. Similarly you can have a bunch of different windows (actual windows, not tabs), but there doesn't seem to be an indication of which window you're in -- you just have to push the "Change Window" button and see if you move, and where too.
6) This is making a strong argument in favor of cloud-based stuff. I literally just switched away from LastPass to a password solution that syncs over the cloud but runs locally, and I'm realizing the Chrome extension is unlikely to work without local storage. Unfortunate.
7) The touchpad is annoying me, but still probably the best I've used that wasn't on an Apple product.
I can't get a right-click menu on Flash ads. I can still kill Flash via chrome://plugins or the task manager, though!