OK, the site I'm running is xblogs.ca
I registered a user's blog for him at "randywriter.xblogs.ca"
Changed all references in the db to the proper location at "blog.randywriter.com"
'blog.randywriter.com' is a CNAME to xblogs.ca and properly points to xblogs. Blog is there, everything works..except..
I go to blog.randywriter.com/wp-admin to sign in, it eventually times out.