One reason I sometimes take sandals is in case I get a blister or something goes wrong with my shoes - then I just hike in my sandals. Also for around camp, gathering firewood and water, you may wish to use your pack and wear your sandals.

An option on this vein though would be to double up lightweight the fabric on the bottom of the pack but leave one edge unsewn on the second layer, forming a sort of sleeve or pocket. Sandals could slide in there adding some protection, not get the rest of your gear dirty, provide a stand to put your pack on, but be readily available. The pack would still be usable without them.

Just my 2 cents <img src="/forums/images/graemlins/smile.gif" alt="" />