I haven't followed this as closely as you. Have you seen this website? If so, then I am way behind and you have my apologies.
http://216.239.51.104/search?q=cache:51-oaACaZ5IJ:nuralcubicle.blogspot.com/2005/07/niger-yellowcake-story-italian-version.html+niamey+2000&hl=en
Behind the Karl Rove and Plame Affair is a plot by three heads of government, Bush, Blair and Berlusconi, to deceive their nations, international institutions and world public opinion for their own cynical and immoral aims. Worse than Suez, worse than Gulf of Tonkin, worse than the Plain of Jars, worse than Watergate and worse than Iran-Contra.
This is an interesting article, although I don't agree with its slant. It indicates that someone at the Niger Embassy passed the file, containing both legit and forged documents, over to SISMI. Rocco Martino has said that an Embassy employee passed the documents on to him, as well. Martino later sold them to the French. So we appear to have one or more industrious Embassy employees. Maybe the break-in was faked, to cover up what someone in the Embassy was doing - stealing stuff so he could sell it to foreign intelligence services.