Serious alternatives to Blueprint or 960 Grid if restricted to modern browsers?

The (Rails) application in question is an internal applicat开发者_高级运维ion and the audience uses modern browsers on various operating systems (FireFox 4, Safari 5, Chrome 10 and IE 9). No need to care about all the old browsers.

Are there any serious (upcoming) grid or fluid frameworks you can recommend despite the well-known Blueprint and 960?

1140px is an interesting one I've been using recently, it's designed to work well on high resolution monitors and degrade nicely on much lower resolution monitors (like phones, tablets, etc). http://cssgrid.net/

One year later: while I really like cssgrid, I find myself more comfortable with Twitters Bootstrap and therefore add this as an answer to my old question :)