I have blogged about Nexenta before, Solaris kernel with Ubuntu userland. It is great if you are familiar with Debian/Ubuntu and want to play with the features in the solaris kernel (DTrace and ZFS got me excited). I was complaining that the www.gnusolaris.org site was quiet and then saw www.nexenta.com , their commercial offering (looks neat, but I prefer free). Turns out there is some work going on for a full release of Nexenta (GnuSolaris is a cool name but both are registered trademarks apparently, and it should probably be called Gnu/SunOS anyhow), see the Launchpad page.
Come on Nexenta, go 1.0.