Do not think about product types. Your just wrapping your head around the wrong thought process there. You should not have to touch product types ever unless you create a new template type as described here
FAQ--How to Create Additional Template Set's in Reviewpost
Everything you want is a category. Users select a category to upload a product to and then users can review that product. Example
Create Category New York. Then create sub categories under New York for areas etc. Users select to upload a product to review to a specific category thats it. Other users comes along and review the product.