Setting up a Regular/Retail/Wholesale store? Do I need to set up 3 Zen-Cart's?

I'm starting to work on a cart for a client who sells Jamaican Sauces and Food Products. She wants it where there are essentially three stores from the same site. One would be a regular retail store, the other would be for supermarkets and other retail outlets (and would be password protected to get in) and the third would be for Wholesale Foodservice operations and the like (also Password Protected). So I'm wondering what the best route to do this would be. Especially since you don't need a Password to get the first store but you will for the other two just to shop. How can I accomplish this and does anyone have any examples?

This also interests me ... I need multiple shops, some with login and some without, and all the shops need to LOOK different, but the product range is the same in every shop.

As well as retail customers, we have very large wholesale customers who each want their shop to appear in their own corporate colours etc.. Ideally these corporate shops would be hosted on completely different websites, but we could compromise by making each shop a sub-domain of one 'master' domain.

So ... can I put the MySQL database on one server and have multiple shops on other servers which all reference the one common database ?

We may soon have 7 shops each with 1000 + products, and the real reason we want a common database is to considerably simplify the process of making price changes !

There's a Multi-Site mod here:

http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=563

The support for the Multi-Site mod is non existent at this time. Many questions asked, zero answers offered. Use it at your own risk.