Here is an interesting project I have found a couple of days back.
Twopcharts made an effort to find the most influential active Twitter users for cities around the world, as well as widely spoken languages. By selecting any of the cities or languages available in their database, you will be directed to a dedicated page with several lists and search capabilities. Twopcharts have also created a number of twitter tools that can be used for any Twitter account. As they say in their about page, they welcome any suggestions you may have.
Here’s an example of what happens if you look for your Twitter account