Scoble is looking for a blogging platform that automatically produces an OPML feed based on tagged data.

Well, I just knocked this index template up for MovableType which seems to do the job. It loads fine in Dave's OPML editor too:

<?xml version="1.0" encoding="<$MTPublishCharset$>"?>
<opml version="1.0">
<head>
  <title><$MTBlogName$></title>
  <dateCreated><$MTDate format_name="rfc822"$></dateCreated>
</head>
<body>
<MTCategories>
<outline text="<$MTCategoryLabel$>">
  <MTEntries>
  <outline type="link"
           text="<$MTEntryTitle 
               remove_html="1"
               encode_xml="1"$>"
           url="<$MTEntryPermalink$>" 
           created="<$MTEntryDate format_name="rfc822"$>" />
  </MTEntries>
</outline>
</MTCategories>
</body>
</opml>

Just add it as an index template, and you're golden. This is working in my install of MovableType 3.2 - I expect it will work fine with TypePad.

The autogenerated opml for my blog is now appearing over here.