we're a team of French developer and we've been using your lib for nearly two years now.
Recently I had to use some more features which I found in the following add on:
http://apps.ultravioletconsulting.com/projects/uvcwebtransform/article/ (also well documented in you blog's comments, user "uvc")
I guess you put HtmlAgilityPack on Codeplex so that it gets a life of its own, but I'm afraid you'll need to move on a little bit for that.
I think Josh did some nice work with his form processorn that you should propose him to join your team and integrate his add on into your core.
What do you think?