BizTalk best practices analyzer 1.1 was released with couple updates. The link: http://www.microsoft.com/downloads/details.aspx?FamilyId=DDA047E3-408E-48BA-83F9-F397226CD6D4&displaylang=en
Keep up to date with BizTalk operations guide: http://www.microsoft.com/downloads/details.aspx?FamilyID=5251f103-329d-4f8d-95b5-64f99f2f6dfc&DisplayLang=en
And finally, I found this one today and I am quite happy with the finding: http://www.codeplex.com/bud. It is a BizUnit designer or in other words GUI for setting up BizUnit test scenarios.