Throne of Games has a Kickstarter campaign running for their Merged D6, a single die that replicates the results of rolling 2d6.
From the campaign:
One of the inconveniences in table-top gaming is having to roll an excessive amount of dice. This holds especially true for those who enjoy role-playing games, such as Dungeons and Dragons. Introducing the Md6, our solution to halving the amount of six-sided dice required to roll. We have agonized over a design that will not only replicate the odds provided by rolling two six-sided dice but will also hold true to the panache dice enthusiasts love. The Md6 not only drastically cuts down on the mayhem of rolling multiple dice, but it also simplifies the math involved, while being the same size as a standard D20.