You might want to consider a small fanny pack instead. Worn on the front, it gives ready access to it's contents, and it can be used to carry items when you leave your pack in the tent.
Ditto that suggestion, except mine is not too small.
It makes a convenient container for camera, ditty bag, FA kit, water purification stuff, TP (don't let Clelland read that:-) and other personal hygiene items.
And topped with a 4x4x1.5 inch piece of open cell foam it makes a very usable pillow.