I had an Old timer with a gut hook for 10 plus years but lost it going through a mesquite thicket. The leather case on the fixed blade wore out and made it easy to slip out.

This is what I got to replace it. It's foldable and the nylon case completely covers it so it's hard to lose and comfortable to wear. The one hand operation is great as well.

http://www.rockynational.com/1360_22-07171_Gerber_Freeman_Folder_Gut_Hook_Fine.html

By the way, it skins real well and holds a pretty good edge.