Love it Richard! I've been thinking about attaching a piece of wood to the friction plate on the runner forever! Never got around to it. Quite the tradition with tree gear naming these days, stiffy, quickie, and now humping wood, oops, woody hump. Have no idea what all that means about tree climbers ;-)
Pretty interesting thinking about wood choices, Lignum vitae aka Guayacan would be awesome. Honey Locust heartwood would be excellent, Black Locust etc. all good.
I suspect if you simply created a flat profile wood baby bump the rope would wear a perfect radius groove pretty quick, experiments needed.
-AJ