This is the second model I created. Many times I have looked at the back of the mirror on my medicine cabinet and wished I could attach a toothbrush horizontally to utilize the unused space and get my toothbrush off of my bathroom counter. So here it is. Print it off attach some double sided tape and apply. It's been working great for me.

Here is my original post http://www.3dhacker.com/category/602/Bathroom/listings/372/Toothbrush-Holder.html