I have a KVM, actually. But it only has AVG, and PS/2 ports. I really don't want to keep flipping it one to another, though. Just the way I am. I have specific mice and keyboards between my 2 systems. AFAIK, you can't do dual monitors with a KVM.
Then I would +1 with either the stand above or finding those pesky studs in the wall.
but... how big is your closet? I saved a ton of actual room space by building into the closet itself. It's an old pic, but you get the picture. View attachment 5275
I'd rather get 2 sets of the doubles. I actually do have another 17" that I can put on there, but not used.
Edit: Actually, now that I thought about it, I can get a triple or quad stand. One that doesn't have a foot per se, but on the bottom have tension brackets that you grip at the back/end of your table. I do have a dropoff on the back of the desk that I can mount it in.