Ajax search plugin

Hi everyone.

I’ve spent 2 days trying to find a plugin and I’m losing my mind. I want to create a front end search. Cascading dropdowns based on three variables and it responds with a forth.

We’ve seen these a million times programmed in Ajax. They usually look like this:

Drop-down 1: Choose your country
The next drop-down adjusts its options based on the result of the first.
Drop-down 2: Choose your state/Province
Drop-down 3 simplifies further to list only table entries matching criteria 1 and 2
Drop-down 3: choose your city

After all three are selected, it fires out all entries in the sql database matching the 3 criteria, such as a list of hotels.

I cannot find any plugins that perform this function. Well, I found one which isn’t compatible with my theme. Has anyone done this in wordpress? Can anyone suggest a plugin?

Thank you.