Just to add fuel to the fire...
I went to a wilderness survival class a couple weeks ago, just for something to do. I used to be a Scoutmaster and used to teach wilderness survival for Boy Scout merit badge. Not an expert by any means and that was a long time ago.
The class was interesting and the instructor introduced us to the Dellbow pocket bow. It was invented by Ron Hood (Hoods/Woods guy) and is basically a carabiner with surgical tube which you use to shoot an arrow. Dave Canterbury has a similar one made from a Wrist Rocket sling shot. I think I saw it on one of his youtube videos.
The other bow the instructor had was one made by www.xspectre.com
I thought it was pretty slick. Even the arrows came apart.
This is probably be the one I would carry in a pack.