Questions about Amazon Affiliate website

Hi All. I've been doing heavy research here and and around the web for a few weeks, and finally am at the point where I could use some questions answered.

I found a niche to sell products based on my own pain points that I feel could be profitable over time, the only problem being that the products are difficult to find wholesale or dropshipped. My plans are to list amazons products on my website, build traffic, approach other established stores for affiliate opportunities, and eventually buy in bulk or manufacture my own product.

What I am trying to accomplish from the start:

• Be able to simplify process of listing of Amazon items on my page. I want images, ratings and comments pulled, and I will highly customize the product listing.
• I would like the items to not appear like Amazon listings, but match the look of my site, or at least be clean and simple looking and highly customizable.
• I would prefer that customers can add items to a shopping cart while on my site, and then be pushed to Amazon for the checkout process.
• I also want the ability to add other products of my own (or from other sources, i.e. eBay) that can have the same look as the Amazon products.
• Ability to create a login to save favorites, wish lists, etc is a big plus.
• I plan on building an email list, so any integrations there is good.

I saw a couple of affiliate Wordpress templates that looking promising for these features, but got very mixed reviews on the forums (terrible support & updates). I guess my main question is what is the best approach for creating this efficiently. Plugin(s) + WP ecommerce theme? Azn Affiliate-specific theme?

I am not opposed to investing in a good plugin/theme to save design & maintenance time. I already have access to all Elegant Themes, if there is something that works with their products.

I appreciate any insight. And links to examples are great too.