You know, I've been thinking about this, and I had an idea. How about a multi-tool? Just stick a Gerber or Leatherman, or whatever brand you have or get, and put it in the top of your hose like that.

Isn't that essentially what a Sgian Dubh was in the first place? A pocket knife for a garment that doesn't have pockets?

It might be too heavy though. Just a thought. Feel free to ignore it.