I just got this http://www.eaglecreek.com/10039.html
At a local retailer, their site has a store locator. A little expensive ($200, but it has a lifetime guarantee) but it is like a suitcase. It has a lot of space, a security wire, and a separate area for dirty clothes.
I was looking at the top down backpacks (wilderness style) and the lady did not recommend it.
Just stuff to consider.