kouri-chan_xx
I don't think that's a Kekkei Genkai... But, you can't use two separate elements! You either have to use them separately, (one after the other) or together as wood, ice, lava, etc...
So, using two elements (one in each hand or something) at the same time, and NOT making a new element, would be interesting. So like, it would be through the hands only... somehow...
Like... left hand is for Fire, and right hand for earth, or something. But, for some reason, they CAN'T make lava release, but instead, they can just use the elements separately from other hands AT THE SAME TIME.