Question defines answer, when you give little details, answer will be brief as well.
I am new too CCTV, but installed cameras in my duplex, its 2 story too, however i put cameras at same height just like if it was one story building, there's no point to put higher otherwise you will have some panorama view without any details, in my opinion its important to capture face of intruder, not just the fact that someone with blurry face or in the hood tried to break into house..
Can you send pictures or house and relative plan of the building i think 10 cameras is overkill unless they want to put some inside house like in garage.
I don't see problem having DVR on second floor, do they have something like security room on second floor with lock in case someone brake down house they lock themselves there and wait for police there, i'd put DVR there otherwise intruded could steal footage, if they too lazy to go up to check DVR they can probably access it from anywhere in the house anyway trough computer / phone.
I hate to install something in concrete walls, but making hole in the floor does not sound too complicated, considering its just one small hole with all camera cords going down trough it, you have to use BNC cord that don't have connectors then add connectors to each wire otherwise hole you need to drill in walls/floor will be huge!
try this too http://bit.ly/1cByL5K