I think there's a lot of people in general, Mac or PC who buy laptops and virtually never move them from the desk.
I went out to a guy's house to install extra memory in his laptop. He says he bought it, put it on the desk and it hadn't moved since. (It was a Toshiba with XP and only 512 MB RAM. He was hitting swap after loading one program due to all the crapware. I cleaned off some of the crapware and upgraded him to 1.5 GB).
There was certainly enough room on his desk for a small form-factor PC or Mac mini, flat screen monitor, keyboard, and mouse. (He already had a mouse. He said he hated using the trackpad!)
Surely the individual items would be cheaper than a whole laptop - and probably faster at the same time, while having the capability of being modular.