I agree completely that this seems a natural fit for the SME Server. As a new user, I only recently came across SME Server because I googled, ""Microsoft Small Business Server 2003" linux alternative". SME is EXACTLY what I need to help me grow my small business - except I need to be able to offer customers a "groupware" product integrated into the server (sadly, like M$ exchange).
It seems that openxchange is the perfect fit (since the source has now been opened - and Novell/Suse will be growing the community).
Anyone have any other info about this?