Hi! I've seen your requirements and tons of experience in developing/customizing wp plugin and themes, I'm top expert in in developing/customizing wp widgets and plugins such as storelocator, sliders with backend manager, utilities, business calculators, management apps etc.
Note: Please reply back if you are interested in my bid, I'll let u know cost and time of this project. My Bid Cost will change once we discuss the project and I'll qoute you reasonable Price, current Bid is 75% of your maximum budget which is not right cost.