I was all set to wait and use a natural branch once I got the chance to go out to the summer cottage but I just couldn't wait any longer and bought a broom handle.
A little bit of carving, filing and sanding and the staff was ready. For the sling part, I was all set to just use one of the cotton string slings I have lying around but none of them were long enough and would have required a fair bit of adjusting to get them the right proportions. I recently got a second Tibetan yak wool sling from Funditor in the Sling In The Hat so with their wide pouch and the fact they're pretty long and have excess retention cord length, I thought they would be perfect. The one from Funditor was a bit too long so I went with the one I had originally and simply tied it on. It seems that with just a simple knot and it sitting in the groove I carved out, it actually stays put. I haven't yet tested it with a heavy rock but I would want to try and keep it from being permanently attached as I like the fact it can be taken off and still be used as a hand sling.
Once the weather improves, I should be able to go out and get some testing done with it and see if the hook needs any adjusting
Also as a side note, I tested out the sling Funditor sent me and these Tibetan slings are great for snowballs