One thing I notice is that I go through a lot of thick brush/vegitation. If I were to mount anything on the sides of the engine cover, they'd get ripped off eventually. I had a fire extinguisher mounted to the top of the engine compartment directly behind the operator seat, and even that got ripped off.
So if you do mount something like a chainsaw scabbard to the side or top of the engine compartment, make sure you are aware of it and how far it sticks out/up. It's easy to forget and run a wheel under a branch yet hit the side of the machine.
Of course, about everyone can tell you to carry stuff in the bucket. I do. That's great. Until you forget there's tools in the bucket and end up burying your saw or chains in a pile of dirt!