Oral-B sells a travel toothbrush - it comes in two parts, the brush sticks inside a holder. Pull the brush out, reverse it, stick the base in the holder, and you have a full length toothbrush.

I also own a camping toothbrush called a "Toob". It is a full-length toothbrush with a protective cover for the brush. The handle of the brush comes off and is a squeezable toothpaste tube. You can refill it - it has an opening in the base that screws onto a standard toothpaste tube, you just squeeze the toothpaste into the "Toob" and you have a toothbrush with toothpaste stored in the handle.