There are not a lot, but I can definitely tell you that there are people out there working on it.
Here is what I know about:
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$1 (available online - it is a described version made by one woman for her friend)
* The Walking Dead - Trade volume 1 - (issues 1 to 6) Please PM me if you are interested in this
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$1 does "Prose Novelizations" of many comics
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$1 \- comic book writers will write scripts. The scripts have instructions for the illustrators. It is important to note that the illustrators will often make different choices from what the author instructed, so the final version of the comic might not exactly reflect the script. This page has a bunch of single issues of comics