I honestly think a 'travel toothbrush' is a solution looking for a problem. I use an electric toothbrush at home but with Quip, that electric brush is no bigger than a regular toothbrush.
And how big/bulky/heavy is a regular toothbrush? Answer - it's not. A toothbrush is small, fits into the corners of your bag, weighs nothing, and is cheap enough to be disposable if you lose it. Why do we need a 'travel version?'