I'm new to the source code so I could be completely wrong, but from what I can see you should be seeing 8 sites in the v75 address bar (I know I do) assuming you have 8 top sites - it seems to share this information with the top sites listed in a "New Tab"

If I am looking at the correct file, and again I admit I am new to the code and could be completely wrong, it is hard-coded to try and grab the top 8 sites. It doesn't seem to refer to any configuration settings so a new config option would need to be added, assuming the UI scales with larger lists of sites.

File: UrlbarProviderTopSites.jsm

 // We want the top 8 sites.
  sites = sites.slice(0, 8);

If this is correct then and enhancement/bug would need to be raised.

Thanks. I haven't fiddled with that file so I assume mine is whatever the default is.

My top sites page is set to 2 rows and shows 12 site icons. Would be nice if they were directly reflected in the urlbar. In the meantime I'm still only getting 5.