Good Start Rated 3 out of 5 stars
It's a good concept but it does need some tweaking.
To begin, I wasn't sure how to access the Auto Dial page despite the fact that you had stated "easily accessible from chrome://autoDial/content".
Fortunately I knew that typing chrome://autoDial/content into the location bar would bring up the Auto Dial page. I really don't think that an average user would know to do the same. A very simple button and /or a keyboard shortcut would easily solve that problem.
For the time being, you can create a toolbar button that will load the Auto Dial page by visiting Michael Buckley's Custom Link Toolbar Buttons page.
Just type in chrome://autoDial/content into the Url: field, pick (or provide) an icon, and you'll get an installable toolbar button xpi. You can dig into the xpi files and change the names and location values as you'd like. An even quicker way (but not as cool) is to instruct people to make a bookmark from the chrome://autoDial/content URL.
Another issue that I have is that the Auto Dial page lists all of the bookmarks addresses. It really should exclude them. I ran Auto Dial in a new and clean profile that only had the default bookmarks. I would have been in trouble if I had used my primary Firefox profile.
In your description you say "Configure how many rows to display by setting the following pref:
But you do not explain how or where that setting can be changed. A power user will figure out that it is accessible through about:config but not an average user.
Finally, the Auto Dial page should be scrollable because I cannot access links at the bottom of the page because they are cut off even in full screen mode.
All in all, it's a pretty cool add-on and these are just my opinions and observations.