Custom Categories per customer

I have a client with a small number of customers who frequently order the same group of products. For example, out of the 15,000 products on the site, they only order from a set of 200, and every month, they might choose 50 out of that 200. So, I'm planning to give them the option to create their own personal categories -- one might be items they order monthly, another every 3 months, or maybe a customer wants to group by the existing categories, but have their own subset.

I'm posting this here to make sure I take the right approach to implementing this. I'm planning on duplicating the category table, with the addition of a CustomerId column (call it CustomerCategories). I'll then duplicate the Product_Category_Mapping table, using the CustomerCategoryId in place of the CategoryId. I'll then display the customer categories above the regular categories in the left-hand column.  This will make it easy for customers to see their personal set of frequently-purchased products, and just enter the quantity to order for each and add everything to their shopping cart quickly.

As for getting items into their own categories, I'll have the regular product listing offer a dropdown for "add to category xxx", plus, of course, a way for them to create the categories.

Does this sound like the right way to implement this feature?

Also, are there any published coding standards I can follow to make sure my code is consistent with the existing code?

sounds like you want to manage catalog access by customer role

go vote for it ond other features:
http://nopcommerce.codeplex.com/workitem/list/basic
specifically
http://nopcommerce.codeplex.com/workitem/7661

Well, that feature might be right -- depends on the implementation. But, I need the feature now, so I will build it. I just want to be sure my approach to solving the problem looks like the right one. Thanks.