While we're on the topic of Gaiman, here is a comic book to which he contributed a story (essay? poem?). There are three cover variations to this comic book. Here is the variation that is signed by Neil Gaiman and Jim Lee.
LIBERTY COMICS #2. The cover of this edition is from the Gaiman/Lee story within.
Table of Contents, featuring stories contributed by various authors and illustrated by different artists:
Note that below the Table, it references two of the covers, "Kick Ass Cover" and "Free Speech Cover." Both of those covers are included in the pages of this special edition.
Inside back cover: This comic book was produced as a benefit for the Comic Book Legal Defense Fund, of which Neil Gaiman is an active supporter.