Yes, some people have. Seeing that most beta tests are under NDA, I imagine that those people can't really go into much detail.
From what I understand, Maya Linux has hit the pre-Gold stage (the last part till shipping). I also heard that 4.0 for Irix is being worked on... I just hope the Linux renderer is released at the same time.
Also, Mac OSX is sexy, so it is going to be shown off... with Linux, you have to play with the default window settings for it to be as attractive. Or... maybe the Apple marketing team has something to do with it.
I do know that that the range of hardware that the Maya Linux 3.0 should be as diverse as it is for the renderer.
-I just program here, how am I supposed to know?