It definetly is under developement, but will not be ready for release before late 2006, at the earliest. I personally think that late 2007 is the more realistic bet, maybe even 2008... These guys don't do half jobs.
Meanwhile you get substantial addons (free) for SB Pro PE with a planned frequency of two times a year (additional features, new platforms, etc).
Basing on beta-tester's feedback I expect that no massive patching will be needed.
Currently they have some loose ends to close together with Pro PE, if they can manage to do so within the next 12-14 days, they say they are confident that they will put the parcels under the christmas trees then.