Hmmm, I think this could depend up on how well things are going a the minute. Are your sites performing well and are they bringing in the customers/leads you are hoping to attain.
There is nothing wrong with having all of these sites, but how do you market other products should the customer land and expect one product, only to find its not quite the one they want. These customer could be leaving without performing an action , yet your other site may have one of the products they desire available, but they did not know.
I would probably suggest having a main branded site that houses all of your items, that way you are able to cross sell your items and people have a greater choice to select from. I would then maybe hold onto these additional micro-sites for any peripheral traffic you have and possibly try drive people to move onto your main branded site.
Just be careful of creating too many sites that link back to yourself which could be seen as a little unnatural. Your micro-sites could be phased out in time once your main branded site gathers pace and develops into a larger presence.
Hope that offers some ideas.