I had the pleasure of reviewing a wonderful multipurpose messenger bag recently, and let me tell you I was more than pleasantly surprised.
The bag is available on: http://www.clothesoutsale.com
Which by the way has some awesome deals on other cool stuff :)
First off this bag is nearly indestructible, as most of my friends will tell you, My finance and I spend a lot of time outdoors, I decided to test its durability during a few weekends of our little excursions. We would put our lunches and a few drinks plus I would shove my purse in there (this bag has amazing storage capacity), and we would do our hiking or camping and dragging it around with us through the wilderness and such. It held up time and time again. It now permanently is in the car, and is our "weekend bag" :)
I think I will also use it once school starts for backpack, because of its simply amazing storage capacity, of course I kinda need to clean it up a bit, and maybe add my "37 pieces of flare" to it beforehand. That is quite possibly the best part about this bag is its durability closely followed by its ability to literally use it for anything.
In conclusion, I think that it was definitely something I would recommend to someone looking for a multipurpose bag/backpack.