You could show me all the engineering charts you have, but I will still feel more confident with rods controlling my rotors over cables. Confidence becomes a real factor when you try to sell your helicopter.
I imagine rods come with a weight penalty, especially for the tail rotor. Also, it seems that FOD would present more of a problem with rods than with cables.
As far as the paint under the floor, just don't make it the same color as any of the fluids that may leak down there. Kinda like those ambulance companies that use red sheets...can you be sure you've got a clean set????