WebsiteForge has a tool that can share your E-commerce database with multiple sites.  This allows you to target different audiences easily with different sites using your core product base.

This tool makes it easy to manage your products for many sites in 1 place.  Imagine you add a new product and BOOM all sites have the new item.  And they can even have different prices!

There is a masking option so you can control what information goes to what site.  

This will allow you to be more flexible with the target audience you are looking to capture with your websites.  Best of all this doesn't mean doubling the amount of work, at least not in the back end of your member's area.  This option will give you a master area where you can update and add your items and inventory, that will update across all of your sites.  You can choose how unique you want the data to be per site TOO!