I think you really need to rethink your current theory. When dropshipping, the cost of the product determines if you will find market at all, it's perhaps the most important factor of all to take into consideration. The number you have the potential to sell directly relates to the cost of the item itself.
What I mean is, I can say that one of the hottest selling items is of course the iPhone, but that doesn't help you if you can't secure at a cost price that will allow you to even compete, let alone a price that will afford you so many sales as to make a monthly margin like what you want.
You mention that you are able to cut out the middle man, but what you have to realize with dropshipping is that most dropshippers suppliers are in fact middle men. They have bought wholesale and are selling with their margin, so you're cost price has already got pressure on it and you're not cutting out any middle man at all.
I think you really need to learn a lot more about the dropship supply chain and the general online sales market itself because your current thinking isn't really going to cut it.