Country, state, city dropdowns by a web service

I created a web service for web admins to easily add country, state and city dropdowns to their site, pasting a bit of code into their forms and pulling in all the data from a web service- see here: https://geodata.solutions
I created a Joomla! plugin so that J! users can add these fields to their custom forms easily (I’m a Joomla developer), and I wanted to see if I could create a module for Drupal users so that they can integrate my web service into their sites.
Being unfamiliar with Drupal, I'm not sure how/where country/state/city dropdowns are implemented into sites, but I know they are a common requirement on a website regardless of the CMS. I think my web service approach is quite novel, removing the need to store and maintain your own dataset.
If there’s any Drupal plugin developers who would be interested in making a module to use the service, then get in touch. If it could be done cheaply, I’d pay to have it developed and release it myself, or you could create it and sell/support it yourself. I’m open to ideas.
I have an API (http://geodata.solutions/rest-dropdown-lists) if the javascript I’m using in the code snippet makes you sick.
I’d just be happy to open up the web service so that it could be used easily by Drupal users if it was any value to them. As far as I’m aware, there’s no country/state/city dropdown solutions for Drupal or other CMSs, which is why I’m keen to push this new 'as-a-web-service' approach.
Let me know what you think.
Cheers
Andy