Happy to report that I got NexentaStor 3.0 nightly 3/3/2010 installed on a test machine. Had one hiccup during the install that required a work around:

1. Go to Console
2. Login as admin / password you set
3. /sbin/su
4. Pass again
5. svcadm enable service/network/iscsi (or something like that). The command is listed at the bottom of the error that is generated during the wizard.

3.0 looks great!!