Just to clarify this, there isn't anything currently built into ClassiPress that will allow you to show all listings under one location (such as Craigslist).
There are no specific plans on the next release of ClassiPress to do this either, although there will be an advanced search functionality which will give users an enhanced way to search locations (and other custom fields of your choosing).
There are no plans in the next release of ClassiPress to allow advertising banners specific to locations the ads are placed in.
One method some customers use to allow a separate lot of ads based on location, is to create a
multisite setup and give each location its own subdirectory. With this and some customization, you can achieve something like this site: fleabay.net
I hope this clarifies things better.