Who said it wasn't related? A "mech" could be any legged vehicular, semi-vehicular, or ambulatory machine. An operator could hypothetically be bestowed within its chassis. What most people see as a "mech" is a stereotypical norm originating from the old Battletech stuff,so forth and so on. Originality is what we need my friend.
I posted that a while ago, so I don't really know what I was getting at... Aside from the fact that this guy mostly draws mechs or robots, and I was thinking about how he would design the vehicle and where the parts would all go.
I know mech's don't need to be limited to that. I have thought of other ways of interpreting it, similar to what you mentioned.