Hacking MarketPress Shipping Form (text field to dropdown box)

On the page “/store/shopping-cart/shipping” it asks you for your address. Where you select your country it offers only a drop down box with only approved countries you set in the admin dashboard.

I wish to do the same thing for the “City” field. My MarketPress is used to offer a service or “installation” of software so to speak. I install the software locally and use these contact details to contact them. I edited the plugin code to change phrases that say “shipping” information to “contact” (ex: Please enter your CONTACT information).

To ensure users don’t use my MarketPress if they are outside of my city I wish to use a drop down box for the “City” field. Only allowing them to select cities I currently offer service to.

I am going to try and hack the plugin myself to do this.. Any ideas on what I should do? I may end up trying to change the “Country” to “City” and modify the country options in the drop down.. I think I would have to change language settings if the plugin code? In that case I would also have to move around fields to display the country somehow and move the old “country” field (now a city field) to the correct location in the form (to follow correct formatting of inputting an address).

Any ideas, input, or knowledge of a fast/easy way to do this would be greatly appreciated! Thanks!