This is a great topic. When I'm sittin in the mountains, I am always trying to invent some great gadget to keep my rangefinder close, easy to get to, and quiet. So far nothing is working out very good.
Since I carry by binos with one of those sliding chest strap things...I tie off my rangefinder to the bino strap and let it hang about 8 inches. This gives it just enough room to not swing into my binos, and also enough room to get to my eye, and a chest pocket easily.
I've also tried wrapping the rangefinder in a camo/soft fabric tape so that it doesn't clang into my binos with lots of noise. That neoprene cover thing sounds like a good idea.