If I were going to replace the fishing equipment (Depending on how much space in the kit it actually took up) I would replace it with Surgical Tubing.

There are a lot of uses for it depending on how much you can actually pack, but in this specific case I was thinking more or less of surgical tubing with a pouch for use in making a slingshot.

Of course my answer may be moot if you're talking about a very small PSK... <img src="/images/graemlins/laugh.gif" alt="" />

Just a thought...

I carry both fishing bits and a slingshot band.