Develop module for prestashop, or modify existing module

I am searching for a someone to help in the development of a prestashop module. Our website is sort of an online marketplace. Only admin creates [login to view URL] products are not for sale, it is an online catalog. Then, third party sellers can register on the site as merchants. They select which products of the ones created by the admin they carry at their stores, and set a price. Then a customer enters the site, searches for a product. On product page, customer must see every merchants' price for that product, the merchants location, and contact info. The idea is that the customer can view many buying options from brick and mortar stores nearby him or not, and compare prices from each vendors. NO sales are performed on the site Key features of the module: - Good backend for merchants. Merchants will have to add their info, including 1 or many physical store locations, and contact info for each store. Then they will have to search through product catalog created by website admin, and select which products they carry in their stores. A merchant with more than one location, must be able to select the store in which he carries the product. Also merchant has to be able to request admin to add a product which he carries but is not in the catalog created by admin. Every merchant will also have to have a small "landing page" where one can see all the products he carries, store locations, contact info, seller rating rating etc. Other options must be available, as: Merchant activate/deactivate products in case he is out of stock, possibly massive price change and so on. - Product page: On product page, customer must easily find and sort through suppliers. A map under product image should pinpoint locations where specific product is sold. Filtering by region, price and seller rating are some other functions. Also customer must be able to write review for each seller (as customer did not purchase on site, there has to be a some filter so not anyone can publish reviews (this could be obligatory facebook login for example) - Review system: The main goal of the review system is to help customers decide which store to go buy, but also to prevent merchants from having "old prices" on our marketplace, or saying they have a product when in fact they are out of stock. Amongst customer reviews, there should be an option for "price in store was different from online" or "went to the store but the product was out of stock". Store admin has to receive these complaints in a separate "notifications" area, so he can contact the seller and tell him to put the correct price, and deactivate product if he is out of stock. I am open to suggestions, additional features and price negotiation. I am aware there are many modules that do many of the above features but not all. Maybe it will be easier to modify an existing module, than to develop one from scratch.