There are now two DVD's and a boot ISO which can be downloaded at
http://ftp.scientificlinux.org/linux/scientific/6rolling/i386/iso/ http://ftp.scientificlinux.org/linux/scientific/6rolling/x86_64/iso/for those who would like to help out with testing or are just curious. I should say that the usual caveats about running test releases apply, i.e. do not run in pruduction environment or on anything mission critical which is self-evident.
SL 6 once again includes IceWM added as a desktop choice for low powered machines or of course if you simply don't like the bigger environments and would rather spend your cpu on something more productive. IceWM is NOT part of the RHEL product which SL is to the largest part a clone of except that it is adding and tweaking a few packages here and there.
This Alpha apparently does not include all the updates from upstream and is missing some difficult packages. That's it, I'm off to try this one out.
As a side note, DistroWatch.com has a review of RHEL 6 Desktop edition this week.