Yes, there is going to be another version of SBS
Since the release of Windows Server 2008 R2, there have been a lot of questions surrounding SBS "Next" and if there will be another version.
The good news is YES....
From - http://blogs.technet.com/windowsserver/archive/2009/10/01/remote-access-smbs-will-continue-to-get-enterprise-caliber-capabilities-with-sbs-and-ebs.aspx
"In fact, we are currently hard at work building the next versions of Windows SBS and Windows EBS. We'll have more on that at a later date."