As of now, no. However, the only way other people will see it is if they specifically search for you using your name or email address - If you want it to be private, just change your name to something else, and link only the friends you want to see it using share, and let them know the reasoning behind changing your name so they don't think you're insane. If you want it really, really private, change your email address associated with the account.
Hopefully Amazon will add a feature like you described in the future.
There is no way to see all of the individual feedback on the Seller. If you want to see individual reviews you will have to scroll or page through all of the reviews on the right hand side of their Seller page.
You can however see a summary of Seller feedback if you look at the Feedback History:
Best Answer
Search for what you need. Once on the listings on the right hand side you will see 'sellers'
Just hit +See more to see all the sellers. Amazon.com should be an option. If not, they don't sell it