So if you move a site from a SPWeb to a SPSite and it is a publishing site you should expect an array of problems and unpredictability.  In otherwords don't make a subweb a top level site.

THIS IS WHY YOU SHOULD NOT DO THIS!  IT IS UNSUPPORTED! http://support.microsoft.com/default.aspx/kb/968483

Gary Lapoint does have a blog on this but it requires direct db modification which again is unsupported.  Although kudos for the effort as it is a nice hack.

http://stsadm.blogspot.com/2007/09/convert-sub-site-to-site-collection.html

I am working on coming up with a supported path to do this, but my hopes are low @ this time.