OK So many warnings here about the fact that long USB cables will probably not work and if latency is involved that's a huge danger, you might not even notice if it's minor, but who wants latency in their recordings. After reading the warnings I wouldn't even try it.
I like the idea of a second monitor. I already use a wireless mouse and keyboard for vocals. I'm not in a closet, but I move back 15 ' away from the DAW just to remove the little bit of fan noise. But I find it hard to position the mouse from that distance so I like the idea of having a monitor close at hand.
Either that or I'm going with the 38" TV.