I have speculated for a while that Armitage is the person Patrick Fitzgerald refers to in pleadings as "the innocent accused." [Again here.]

Empty Wheel at The Next Hurrah and Tom Maguire have written extensively about Armitage.

Also, it's interesting to note that Libby has written in several filings that he intends to call Armitage as a defense witness. From the May 12 Libby filing (pdf):

So far, the defense has identified by name the following current and former government officials as potential defense witnesses: (1) Richard Armitage; (2) Colin Powell; (3) Stephen Hadley; (4) Bill Harlow; (5) Karl Rove; (6) Joseph Wilson; and (7) Valerie Wilson. See Mot. at 15-16. All of these persons were discussed by Mr. Libby during his grand jury testimony, and the indictment refers to the latter four either by name or by implication.

The defense seeks documents from the files of these witnesses - and others - that relate to former Ambassador Joseph Wilson's trip to Niger and his wife's role in planning it. During oral argument, defense counsel agreed to limit these requests to the category of documents that is most critical to the defense: documents created, sent or received after May 6, 2003, when the controversy relating to the "sixteen words" erupted, and certain government officials began to discuss Mr. Wilson and his wife with reporters.

In a