Research is certainly king in e-commerce, the more you research, the more you increase your chances of success. Unfortunately I have no clue as to any current niche markets and if I did, then I would probably be taking advantage of that knowledge myself lol, but that's where research comes into it.
I tend to think that the word "niche" gets throw around a little too casually these days. True niche markets are very difficult to find and most people end up stumbling upon them just through test marketing products and that for me is still the best way to confirm any market. That's the beauty of dropshipping, it provides you with a cost effective avenue to test market products and develop markets.
You really don't need to find a "niche" market as such, you just need to find markets that aren't saturated and have a steady, even if slow, sell through rate. Put enough of those type of markets in your back pocket and you can start building a successful e-commerce business.
It is of course just my own opinion, but if you aren't using a wholesale business model and a very good one, then you're far better just staying clear of saturated high turn over markets because the competition is just too heavy. There are some exceptions to that of course, one of those is looking at bundling options to break into that type of market for example, but going product to product, dropship is never going to cut it against a wholesale seller.