It's my understanding that the CSS Flexible Box Layout module is being rewritten and that display:box is being deprecated in favor of display:flexbox.
Is display:flexbox currently supported in any browser (release, beta, or nightly)? Does anyone know where I can find some information as to what's new in flexbox, what the differences are between it and the old module, and/or why the old module was rewritten?
It looks like at this time good information is not available. I will update this post if and when I find good information.
Update: (2/20/2012) caniuse.com now shows the browser support for both the new and old versions of the Flexible Box Layout Module
Update: (8/7/2012) Chris Coyer has put together a nice article about how to tell the difference between the new and old syntax. http://css-tricks.com/old-flexbox-and-new-flexbox/
Compatibility table for flexbox support
In short: IE10+, Firefox, Chrome, Safari, iOS and Android.
As you mention, the official values for "display" in the Flexbox spec are "flexbox" and "inline-flexbox", as of the March 2011 Working Draft. The "box" value was mentioned in the first Working Draft (July 2009) and is the one that has most widespread support at the moment, but should now be replaced by "flexbox".
