I saw this Instructable
for a toilet paper holder that could be mounted on a wall and then pulled toward the toilet, and thought it was awesome. I have a house rabbit, and any toilet paper under 2' off the ground becomes a play toy. Of course, I started making the holder and then changed the design part way through. So, here's my version of iminthebathroom's Go-Go Gadget toilet paper holder.
My version has a commercially available toilet roll holder mounted on the Ikea mirror holder. I thought that was all I'd need, but it turned out that, since the roll holder is now mounted 90° from what it's designed for, the roll falls off.
The fix was to attach a cabinet knob that matched the rest of the bathroom hardware. The roll fits over top, but then bumps up against it when in use instead of falling off. It also gives you something easy to grab when moving the roll away from the wall, or tucking it back.