There are some add-ons that will give a count such as how many locations in a certain city, that would be directory builder.
there are so many variables that you set to get the results you want it would be pretty tricky.
For instance you are asking for number to come back in the searchers area. that would indicate that one would need to know the location, either through location sensor or IP address. Browsers work differently on those accounts. ( See location sensor documentation) and what would come back if a searcher browsed or search incognito? It would come back as no results and that probably isnt what you want. The search and query to Google is based around radius (which you set) of either the map, or default for the search. (How SLP search works)
It is an interesting concept though, and you can query the developers to see if it is possible to customize something like that for you.