Looking for WP Template

I am looking for a wordpress template that will allow me to do the following

  1. I want to set up a site that will act as a review/rating site for websites with categorized listings.

  2. The users can submit their website with required information.

  3. The backend should automatically take a website thumbnail based on the URL that user submits during submission step.

  4. Every new submission will go into pending/draft status as admin will have to approve it before it gets published on the site.

  5. On the front end, users will be able to see categorized listing with standard features such as tags, featured listings etc.

Which WP template is suitable based on the requirements listed above?

I’m afraid you will have to make it from scratch with some special plugins.
Or maybe there’s premium theme that will suits your needs after some customization (like woothemes snapshot theme).
Other possibility is maybe WPMU.

You need to create a custom theme for all this and then you need to use few additional plugins for doing all this as this kind of requirements are unique and sorry to say no theme is created yet according to your requirements

What would be the reasonable time and cost estimates to get this kind of custom theme done?

You can check out the following theme:

InReview Wordpress Theme | Elegant Themes

I hope it helps =)