How do I get my hands on ProClarity 6.3?

You can get 6.3 through the MSDN, MVLS, the fulfillment desk 1-800-248-0655, or via an evaluation copy at the public http://download.microsoft.com site.  6.2 hot fixes are no longer available since the product version is no longer supported.  You must upgrade to 6.3 to receive support and updates. 

 -Joey