Thanks for asking about my books and other formats.
I only have the ebook rights for a few of my books, so I don't get to call the shots on the availability of the majority of them--my publisher does.
For the few I do have the rights to, I haven't found major distribution sites that allow authors to, in effect, "self publish" in other formats. For example, if you go to the author page for Fictionwise:
http://www.fictionwise.com/authorinfo.htm
You'll see that you need at least 10 works that you have the rights to before you can work with them.
Are you aware of well-regarded ebook distributors for other formats who will work directly with authors?