So - in Star Wars games and movies (the I,II,III,IV,V,VI episodes) we had practicaly only 2 types of lightsaber - single hilted and lightstaff. Dual lightsaber is not a type, but an style of using this weapon. I think there should come with something new. I know it will colidate with fact that there will be no such thing in future of SW world, but what the heck. Althought my english still need's to be worked with, here are some of my ideas:
1. Lightscythe. Perfect weapon (at least for better look's) for an Dark Jedi\Sith. Imagine a Sith Lord, dressed in black cloak, skeleton mask on face and with hood on. In hands he wields a Lightscythe, which can be combined with my other idea - the Corrupted Crystal (which project's covers the beam with dark matter, making it black). So, he stands before you, talking to you with an dark, low voice, then you can fight him, kill him, take his stuff
2. Fistsaber. Two of these babies could give whole lotta fun. This can be difficult to describe, but it can be done like this: on grip there are 4 ring's which through you can put your fingers. Mounted to it is the hilt, which is saber's blade shaped. The beam is not as in normal lightsabers, where it comes out of the top of hilt and it creates a long blade. Here it comes out of the part, where you would usually hold it. Damn, I wish I could show it to you on a picture, but I hope you get what I mean.
Because all of this is nowhere to be found in in the films or games (I don't know if anything of this were in the comic or book series, because I have not read them), it should be unique. Very limited, or only one of each created.
I don't want to get anymore creative, because it would go to far I guess. I already had an idea for an Lightshield and Lightbow, so that will be all I propose for now